With the rapid development of China's economy and the improvement of the internationalization level of enterprises, the importance of internal audit of enterprises is increasing. Due to the complexity and uncertainty of the social environment and internal personnel faced by enterprises, the difficulty and risk of auditing are increased. How to ensure the quality of enterprise audit work and prevent audit risks has become one of the main problems that enterprises need to solve at present. 1 causes of internal audit risk of enterprises The internal audit risk of enterprises mainly comes from subjective and objective factors. Objective factors, risks brought by weak internal control system of enterprises. Whether the enterprise's internal control system is perfect and its operating conditions are stable is the basis for implementing audit supervision. If there is no internal control system, or the internal control system is ineffective, it will directly lead to the difficulty of controlling risks. Furthermore, the more complex the enterprise management mode and the more complex the internal management level, which means that the more difficult the audit is, the greater the possibility of mistakes and mistakes in the audit work, and the greater the audit risk. The independence of internal audit institutions is not enough. The internal audit institution is the internal organization of the unit. It works under the leadership of the person in charge of the unit and serves the unit. Therefore, the independence of internal audit is not as good as social audit, and it is inevitably restricted by the interests of the unit in the audit process. Internal auditors are faced with the relationship between leaders and unit leaders, and between departments and colleagues. The people involved are either leaders or colleagues, and there is no direct relationship or indirect relationship. The audit process and conclusion must involve specific personal interests, so the audit process is inevitably interfered by various people. The relevant laws and regulations are imperfect and the legal environment is constantly changing. A sound legal system and a sound legal system are the legal guarantee to protect the legitimate rights and interests of auditors and reduce audit risks. However, due to the continuous development of economy and society, audit work is in a constantly changing legal environment, and the lag in the formulation of laws and regulations in China makes auditors lack the protection of corresponding laws and regulations. The irrationality and lack of operability of laws and regulations also increase the difficulty of auditors' work, which correspondingly increases the audit risk. Enterprise audit business is complex, and the scope of audit is constantly expanding. With the rapid expansion of enterprises, the audited business has become increasingly complex, which brings more difficulties to internal audit. An enterprise is no longer a single operation, it may involve many industries and its business is very different. In addition, more and more financial derivatives are used by enterprises, which will easily lead to more complicated accounting information systems, increase the possibility of errors and omissions in accounting records, and bring difficulties to the audit work of enterprises. At the same time, the audit scope of enterprises has not expanded much, including not only financial audit, but also the evaluation of enterprises' sustainable operation ability. It is more difficult for auditors to express correct and comprehensive audit opinions through financial inspection, thus increasing the occurrence of audit risks. Subjective factors include uneven professional quality of internal auditors. The quality of auditors is the main factor that determines the audit risk. The quality of auditors includes the level of policies and regulations, professional knowledge, experience and skills, audit professional ethics and job responsibilities. Audit experience is an important skill that auditors should have, which needs to be accumulated in practice. Many internal auditors in our country are only familiar with financial accounting business, and some auditors are not familiar with the business activities and internal control of their own units. Limited audit experience. In addition, the work responsibility and professional ethics of internal auditors are also factors that affect audit risks. Because there are still some gaps in China's internal audit standards, work norms and professional ethics, many internal audit institutions and personnel lack the restraint and guidance of due professional norms. In a word, at present, the overall quality of internal auditors in China is low, which directly affects the depth and breadth of internal audit work. Faced with the complexity of internal audit objects and the expansion of contents, internal auditors are in a weak position, which will directly lead to audit risks. The limitation of internal audit and the risk brought by the defect of audit means. First, in China's enterprise management, internal auditors are not only the subject of supervision of enterprise management activities, but also the object of implementing enterprise management activities, on the one hand, they should safeguard national interests. On the other hand, it is necessary to safeguard the interests of enterprises according to the will of operators. When there is a conflict between national interests and enterprise interests, some auditors often choose the latter, which naturally violates the auditing principle and increases the auditing risk. Second, the audit technology has developed from manual audit in the past to computer-aided audit now, which has greatly improved the quality and efficiency of audit work. However, there are still some deficiencies and defects in auditing techniques and means. Judging from the current technical effect of enterprise internal audit, it has not achieved the best audit effect. Therefore, the limitation of audit bureau and the lag of means will inevitably lead to audit risk. Ignore the risks brought by the audit. The development of audit work is a process of continuous exploration. In recent years, due to the transformation and reorganization of enterprises, the establishment of modern enterprise system and the standardization of corporate governance structure, internal audit has been paid more and more attention. However, in practical work, many managers still lack the necessary understanding of the role of audit, only regard audit as a procedure to verify financial data, fail to play the role of audit supervision, and some even avoid talking about it, resulting in the lack of corresponding status of audit in management, which greatly reduces the status and role of audit, not only unable to compete with the independence and authority of audit juice.