As a product in the period of China’s planned economy created by the shortage of materials, unified purchase and sale is a complete system. The system is strictly controlled and managed by the state through fixed production, purchasing, transaction, sales and fixed consumption in order to control the supply and demand of agricultural products completely. The state not only extends the state power longitudinally from the central to the countryside, even to the peasant family, but also extends state power laterally to the area of social production, distribution, exchange, circulation and consumption of the agricultural products. Thus, it completely controls the whole process of the social production of agricultural products, gives the national characteristics of agricultural products, and strengthens the national identity of the community, as well as achieves the purpose of social penetration and integration.