Abstract: In the revolutionary period of the new democracy,Sun Yetsun's Three Principles of the People played an outstanding role in Chinese communists'inheritance of the Chinese national cultural heritage.In the anti-Japanese period,an ideological phenomenon and cultural phenomenon appeared within the Chinese Communist party,that is,research on Three Principles of the People,which plays a promoting role in the development and perfection of the theory of New Democracy.This paper demonstrates its role from the perspectives of why it was needed,how it was manifested,how it was possible and what it was.