Yang Le, a famous mathematician and academician of China Academy of Sciences, said that it is an important task for graduate students to receive complete scientific research training and make a qualified dissertation under the guidance of their tutors. At present, some postgraduate training units have rigid regulations: to obtain a degree, at least one SCI paper must be published, and even the total number of papers is required. The effect is not good, because making one or two meaningful papers at the graduate stage does not mean that students have received complete scientific research training. Only by receiving complete research training under the guidance of their tutors does it mean that they have the ability to engage in research independently. The first step of complete scientific research training is to choose a topic. What we want to choose is the research field and direction that we will be engaged in for a long time or even a lifetime in the future, so it should be an important field or direction that the international community pays attention to at present and has a bright future. In addition, the topic should be selected according to your own interests, and the school and tutor should also be considered. The topic of the dissertation should be appropriate and broad, so as to master the theories and methods in this field and direction, and it is difficult to become an excellent dissertation if the discussion scope is too narrow. Of course, we should pay attention to the tutor's opinions when choosing a topic, but the idea of "I will do whatever the teacher gives me" is not desirable, because most teachers have two kinds of problems in their minds: one is the famous problems in his research field, such as Riemann conjecture and Goldbach conjecture on number theory, which have been in his mind for decades and hundreds of years, and many famous scholars have not studied them, so the topic selection of graduate thesis is certainly inappropriate; Another kind of question the teacher already knows what to do, even has done it, but he doesn't publish it because he feels meaningless. If the teacher gives you this kind of problem, he will definitely let you work it out, but it's not interesting. The above two questions, the first one is too difficult and the second one is too worthless, are not good topics for the paper. Reading literature is a very important part of research work. Literature often contains classic works and the latest literature in a field. The so-called classic works are usually the works of academic founders in this field and direction, which may have been produced twenty or thirty years ago, but until now, their theories and methods still play an important role. If you don't master them, you will lose a tool and a weapon. If you understand it, you can reach the forefront of this field as quickly as possible. In addition, every field and direction is constantly producing new achievements, so it is necessary to master the latest literature, otherwise it may have taken a lot of time to make some achievements, but finally it is found that this achievement has been mentioned in an article published by a scholar in the United States or Western Europe two years ago. Efforts are the most decisive link in research work. It is never easy to get any valuable results, but it is always a deliberate exploration. Often when you feel cornered and ready to give up, you have actually entered a critical period. At this time, you must stick to it and consider exploring in other ways. Hard work requires strong perseverance and indomitable spirit. If you stop halfway, there will be no subsequent achievements. After studying the literature and tackling key problems, we have achieved meaningful results, so we should pay attention to expanding and expanding these results. Sometimes, thinking about the results and treatment methods from another angle may get more valuable results. Finally, the written part of the paper is also very important. A paper should be rigorous in reasoning, fluent in expression, clear and easy to understand in narration and beautiful in form.