Since the reform and opening up, the discussion on whether May Fourth Movement is the beginning of the new democratic revolution has been a hot topic in academic circle, and the debating focus lies in how to understand the nature of May 4th Movement. New democratic revolution in fact has the meanings in such narrow sense and in broad sense. New democratic revolution in narrow sense is the democratic revolution led by the proletariat while new democratic revolution in broad sense is the democratic revolution in China after the Russian October Revolution. May 4th Movement produced the factors of new democratic revolution, was the beginning of new democratic revolution in narrow sense and was also the beginning of new democratic revolution in broad sense. New democratic movement led by the bourgeoisie after May 4th Movement was old democratic movement itself in nature but has significant nature of new democratic revolution because of its unification with the revolutionary movements led by the proletariat 