When Cai Yuanpei was the president of Peking University, he determined the school-running policy of "freedom of thought" and "inclusiveness" as the guiding ideology for the transformation of the old university. He believes that universities are institutions that study advanced knowledge and should advocate freedom of thought and academic freedom. All factions hold that as long as there are legitimate reasons, stick to their own reasons and do not reach the fate of natural elimination, they can develop freely and tolerate.

According to this policy, he hired teachers to "concentrate on learning ideas" and allowed people with different academic viewpoints to teach in universities at the same time, which made the faculty of Peking University full of talents and took on a new look. His school-running policy changed the quiet scene of the old Peking University, played a positive role in breaking through the long-term cultural absolutism in China feudal society, provided favorable conditions for the spread of various new ideas in university forums, and made Peking University the birthplace of the May 4th New Culture Movement.