Considering the phenomenon of "free ride" in the market, the single - species and double - species evolutionary game model were constructed respectively to analyze the quality control strategy space between dairy processing enterprises, dairy processing enterprises and government regulators and its evolution trend. The results show that there are three evolutionary stabilization strategies in the single population game between dairy processing enterprises and in the double population game between dairy processing enterprises and government regulators, which are affected by the "free ride" income, the cost of enterprise quality control and government punishment. Improving the awareness of quality and rights of consumer, increasing the government's punishment, reducing the quality control costs of dairy products, expanding the price difference of dairy products between the finer and the inferior can effectively prevent the "free rider" behavior, and promote the healthy development of China's dairy industry.