While exploring the deep mechanism and internal roots of human activities, Freud tried to analyze and explain the psychological reasons behind human behavior motivation and behavior from the perspective of the unity of human natural biological nature and human social and cultural attributes, and the results were embodied in Freud's personality structure theory. Personality structure theory is an important development of Freud's later thoughts. His personality structure theory, early subconscious and instinct together constitute the three theoretical pillars of his psychoanalysis. This paper attempts to analyze the emergence and development of Freud's personality theory from the perspective of historical materialism, and points out its rationality and limitations. The structure of the paper is as follows: The first part is an overview of Freud's personality theory; The second part discusses the characteristics of personality theory from the relationship between personality research and human nature research; The third part discusses the characteristics of personality theory from the relationship between human natural essence and social essence; The fourth part discusses the characteristics of personality theory from the relationship between rational activities and irrational activities. First, the basic content of Freud's personality theory In the early stage of Freud's thought development, he applied the concepts and methods of topography to psychology, and divided people's psychological activities and structures into three parts: subconscious, pre-consciousness and consciousness. The generalized subconscious can include pre-consciousness, focusing on describing different levels of psychology and studying the laws of subconscious activities. In his view, people's psychology is like an iceberg floating in the sea, a small part of which is consciousness, and most of which is subconscious, which is the basis of consciousness. Not only the individual's behavioral motives, but also the whole human activities and the development of civilization can be found in the subconscious. In the later stage of Freud's thought development, he was no longer satisfied with describing the relationship between different levels of psychological activities with psychological topography in the early stage through long-term arguments with different schools and different viewpoints. Gradually revise and develop your own theory, focus on the dynamic system of psychological activities, and establish a new personality structure model. Freud believed that a complete personality structure consists of three systems, namely, ID, ego and superego. For a mentally sound person, these three systems are a harmonious and unified whole, and their close cooperation enables people to effectively communicate with the external environment in order to meet people's basic needs and desires and realize people's lofty ideals and goals. On the other hand, if the three systems of personality are difficult to coordinate and conflict with each other, people will be in disorder, internal and external difficulties, activity efficiency will be reduced, and even people's survival and development will be endangered. The id is located at the bottom of the personality structure and is obtained through heredity. It is inherent in the human body structure and has the instinct of spiritual expression. Id is expressed through impulsive behavior and image formation, and it pursues the principle of happiness. The spiritual field between the ID and the outside world is the ego, which is developed on the basis of the ID, formed in the process of parents' training and dealing with the outside world in early childhood, is the "administrative organization" in the personality structure, and is the realistic ID, that is, on the one hand, it accepts the requirements of the ID to pursue happiness and avoid pain, on the other hand, it must face up to the conditions of the external real world and distinguish the subjective psychological world. The superego is a moral self, which is developed from the self. It is a judicial department that specializes in morality in the personality structure. It is based on "self-ideal" and "conscience" and pursues the ideal principle. Id, ego and superego have important differences and close ties. From the difference point of view, id represents genetic factors and is a biological instinct inherited from people; Self is mainly determined by personal experience and social environment, that is, accidental and contemporary events; Superego represents the ideal of the outside world, which is essentially inherited from others and society and influenced by parents and their substitution. In terms of connection, ego and superego are derivatives developed on the basis of id. At the same time, ego is the central system of personality structure, and it is the controller and regulator of human behavior and motivation. It constantly juggles with the id, the real environment and the superego, balances and coordinates their relations, bears the pressure and challenges from all sides, and avoids the anxiety and disintegration of the self to the maximum extent. Superego is different from ego. It is the guardian of social and cultural traditions and the arbiter of moral norms, imposing its own likes and dislikes on the individual. Freud believed that personality structure is not a static energy system, but a dynamic energy system. Once it is formed, it is in constant movement, change and development. The fundamental driving force of personality formation and development comes from psychological energy, which comes from instinct, that is, human desire and impulse. Id is the repository of psychological energy. It releases energy by reflecting activities and realizing wishes. In the process of releasing energy, I will encounter the resistance of self and superego. If my instinct breaks through the resistance, my rational activity process will be destroyed. If I break through setbacks, my energy will be transformed into the driving force of my own and superego activities. Freud believes that both the growth and development of individuals and the development of human cognition are the process of self-conquest and breaking the narcissistic state of the ID. It is precisely because of the self's full and effective restraint and control of psychological energy that a new objective venting effect is formed, which enables people to use energy other than satisfying instinct to develop people's psychological process and transform energy from the irrational psychological process of the ID into a rational psychological process. Self-ideal and conscience of superego have a reward and reward mechanism, which puts energy into the venting of ideal energy. Generally speaking, psychological energy enters the self and then the superego through the mechanism of seeking common ground. Psychological energy also follows the law of energy conservation and transformation, and its different distribution in personality determines the nature of a person's behavior. Id only has the function of energy venting, while ego and superego have the function of energy venting and anti-energy venting. The contradiction between energy venting and anti-energy venting makes people feel anxious. Anxiety is a painful emotional experience, and it is a warning signal. Freud divided anxiety into three categories: realistic anxiety, nervous anxiety and moral anxiety, which are self's fear of environment, id and superego respectively. Freud believes that the change and development of personality is that people try to alleviate and eliminate setbacks, conflicts, pains and anxieties, and through some methods to adapt to and overcome psychological obstacles, the role of personality is kept continuous and regular, and finally individual unique personality is formed. These methods mainly include: seeking common ground, displacement and sublimation. Seeking common ground means that a person brings the characteristics of an external thing, especially the characteristics of others, into his own personality system. Freud believed that there are four types of seeking common ground: narcissistic seeking common ground; Goal-oriented, seeking common ground while reserving differences; The object has lost the function of seeking common ground; Forcing common ground. Displacement refers to the process of transferring psychological energy from one object to another. If the object of replacement is a higher goal in the social and cultural field, this replacement is called sublimation. Freud believed that the sublimation of instinct is an important source of human civilization. In addition to the above-mentioned methods of affirming reality to eliminate psychological tension, we can also use the method of denying reality to alleviate people's anxiety. This is the self-defense mechanism, which includes inhibition mechanism, projection mechanism and reversal mechanism. Second, from the perspective of the relationship between personality research and human research, personality theory Marxism holds that "the theoretical thinking of each era, and thus the theoretical thinking of our era, is the product of history, with very different forms in different times, so it has very different contents." The emergence and development of Freud's personality theory is no exception. As we all know, the Renaissance in modern Europe held high the banner of humanism, opposed the strangulation of human nature, and advocated "the return of human nature", thus creating a new era of respecting and studying human beings. Modern science first broke through the forbidden area of human beings, physiology, anatomy and psychology were separated from philosophy one after another, and the science about human body made great progress. Modern philosophical research also pays attention to human problems. At that time, philosophers mainly had two views on human research. One is to regard man as a perceptual reality that is purely restricted by natural laws according to the biological point of view; The other is to regard man as a spiritual entity free from material entanglement and natural constraints according to the viewpoint of energy theory. 19th century, with the development of science, the study of human beings has become more in-depth. Modern western philosophy absorbs scientific theories such as biological evolution, transcends the abstract opposition between materialism and idealism, abandons rationalism dogmatism represented by Hegel's philosophy with irrationalism and humanism, and produces irrational philosophical thoughts such as Schopenhauer's will to life and Nietzsche's will to power. It should be said that this greatly enriches and deepens the study of human beings from one side, and also provides a philosophical basis for the emergence of Freud's psychoanalysis. Freud's personality theory inherits the significance of the development of modern western science and philosophy. It is the fundamental purpose of Freud's theoretical exploration to care for, examine and study people and uncover the mysteries of subconscious activities and personality psychological development in the depths of human soul. Freud's personality theory is rich in connotation and distinctive in characteristics, which are highlighted in two aspects: First, the systematic characteristics of personality. Freud always regarded man as a system with different levels and functions. In the early stage, he focused on describing the depth of psychological space, divided people's psychological activities into three areas: consciousness, pre-consciousness and subconscious, and elaborated their different functions. In the later period, I focused on the systematic thinking and dynamics of psychological personality, and expressed the three components of psychological activities with ID, ego and superego respectively, and deeply discussed their different functions and their internal relations and development relations. The second is the development characteristics of personality. Freud absorbed the achievements of modern natural science, regarded man as a dynamic energy system, observed the laws of physical chemistry, and studied human psychological activities and personality characteristics, that is, studied the structure and evolution law of human dynamic psychological energy system. The formation and development of personality structure depends not only on the interaction between internal energy venting and anti-energy venting, but also on people's adaptation, seeking common ground, displacement and sublimation to the real environment and social civilization norms. From these two basic characteristics, it is not difficult to see that Freud's personality theory not only got rid of the traditional psychology's practice of constructing personality psychology from single-level and static psychological activities, but also reconstructed a multi-level complex psychological personality system from subconscious and consciousness, id and ego, ego and superego, and got rid of the traditional philosophy's practice of defining human nature simply from human external forms or certain abilities. Paying attention to the formation process of people's spiritual activities and personality characteristics in the relationship between people and the environment, individuals and others, individuals and society, thus greatly enriching the understanding of the essence of people's spiritual activities and enriching and deepening the research on people themselves. Based on this, Freud's personality theory and research methods have great enlightening significance for later personality psychology and human research, which goes far beyond the field of psychology and has a great influence on the field of human studies in modern western philosophy. It should be pointed out that Freud's personality theory has two limitations: first, it emphasizes the explanation of people's real existence and behavioral motives from the aspects of people's psychological activities and spiritual activities, while ignoring the decisive significance of social material and cultural life to people's psychological activities and spiritual activities, which makes his personality theory painted with subjective only ability; Secondly, he limited the psychological basis of personality theory to unhealthy people such as mental patients, which affected the universality of personality theory. Thirdly, judging from the relationship between human's natural essence and social essence, personality theory examines the overall composition of personality from the perspective of the differentiation and development of human's psychological activities, which inevitably involves human's body and its active objects. Therefore, personality theory is not only a kind of psychology (or psychological philosophy), but also a unique model of human nature theory and human nature theory.