Abstract: The happening of the Movement the People's Communization contains rich social and historical causes, but the social thoughts of left inclination is also an absolute cause. Especially, the Utopian idle thoughts, the overstepping thoughts, the class struggle thoughts which are customarily-formed in China history, the subjective ideal thoughts which are separate of the objective reality, and the traditional unrealistically obeying have become a universal phenomenon during the Movement the People's Communization in 1958. These social thoughts had a great effect on the appearance and development of the People's Commune.