It was believed that the public canteens of the city peoples communes resulted from the “Big Leap”. It justifies the conclusion, to some extent. However, it only elaborates the social roots that emerges the public canteens of the city peoples communes from the practical perspective. Essentially, there are complex reasons for it. Apart from the practical side, theoretical, ideological and social roots have played significant roles, among which the ideological root is the major cause. In other words, external cause makes up the ground of change, while internal cause makes up the condition.