1. Further testing and verifying the author's understanding of the thesis and his ability to demonstrate the topic on the spot is one of the purposes of organizing graduation thesis defense in colleges and universities. Generally speaking, from the papers submitted by students, students' understanding of their own papers and their ability to demonstrate topics can be roughly reflected. However, due to various reasons, some problems have not been fully expounded, some may be limited to the overall structure, some may not be developed due to space constraints, and some may be that the author thinks this issue is not important or does not think it is necessary to elaborate; Some of them are probably the weak links that the author deliberately avoided because he couldn't go deep or didn't know clearly, and some may be the shortcomings that the author didn't realize at all. By asking and answering these questions, we can further find out what the author didn't do in-depth analysis, so as to understand the students' knowledge, understanding depth and ability to demonstrate the topic on the spot.

Secondly, the second purpose of organizing graduation thesis defense is to further investigate the depth and breadth of professional knowledge mastered by the author of graduation thesis. Through the examination paper, we can also see the depth and breadth of the knowledge that students have mastered. However, the main purpose of writing graduation thesis is not to examine the depth and breadth of students' knowledge, but to examine students' ability to analyze and solve problems independently by comprehensively using what they have learned, and to cultivate and exercise their ability to conduct scientific research. Some knowledge used by students in writing papers has been mastered and can be used comprehensively; Some may have a little knowledge and have not turned it into their own knowledge; Others may mechanically copy other people's articles, and the basic meaning is not clear. At the defense meeting, members of the defense team put forward some unclear, unlucky, incomplete, inaccurate and imperfect opinions in the paper, so that the author can answer them on the spot, so as to test whether the author has a deep knowledge base, creative opinions and sufficient and solid reasons for the issues discussed.

Third, the third purpose of graduation thesis defense is to examine whether students finish their graduation thesis independently, that is, to test the authenticity of graduation thesis. Writing graduation thesis requires students to complete it independently under the guidance of teachers, but it is not done under the strict supervision of teachers like exams, but in a long period of time (usually one semester), it is inevitable that a few unconscious students will take chances and cheat by various means. Especially in open universities such as TV University and Correspondence University, students have a wide range, a large number, a large number of students, loose organization and uneven quality, and it is difficult to put an end to unhealthy trends such as ghostwriting and plagiarism. Instructors must be strict, but it is difficult for a teacher to guide multiple students on different topics and different ranges of papers. The defense team or defense committee is composed of more than three teachers, so the ability to identify the thesis is stronger. Through the questions and defense at the defense meeting, cheaters can be exposed, thus ensuring the quality of graduation thesis.

For the respondent (the author of graduation thesis), the purpose of defense is to pass, graduate on time and get a diploma. If students want to successfully pass the graduation thesis defense, they must understand the purpose of the graduation thesis defense organized by the above-mentioned schools, then make targeted preparations, continue to further scrutinize and study the related issues in the thesis, make the basic materials mentioned in the thesis accurate, and thoroughly understand the basic theories and viewpoints of the article.