1. Time and purpose: Pre-defense of doctoral students is conducted before submitting doctoral thesis, aiming at enabling graduate students to discuss the research contents, methods and achievements of the thesis with their tutors and members of the defense committee, and give feedback. The purpose of pre-defense is to help graduate students improve their papers and prepare for formal defense. Formal defense is the final defense after completing doctoral thesis and passing pre-defense. In front of academic experts, the purpose is to comprehensively examine graduate papers, verify their research achievements, academic contributions and academic abilities, and decide whether to grant doctoral degrees.

2. Content and form: Pre-defense focuses on the discussion and feedback of the contents, methods and results of the paper. Graduate students should show their research results to their tutors and members of the defense Committee, and answer questions and questions raised. The form of pre-defense can be group discussion, academic report or the like. Formal defense requires graduate students to give academic speeches in front of academic experts and answer questions raised by experts. Graduate students should fully display their research achievements, academic contributions and academic abilities, and prove their in-depth understanding and mastery of the research field. The form of formal defense is an open academic speech and a question-and-answer session.