Abstract: The article is based on the responsibility system framework of incomplete information theory, in view of the regulator, the original food manufacturer, the new food manufacturer and the consumer, and step by step to decompose the behavior and analyze the earnings of multipartite subjects, and tear down the constraint and the equilibrium in the optimal food safety level. The study founds that, the government have to keep the objective and fair regulation for both the new food manufacturer and original food manufacturer, both several reward and punishment, and have to control the extent of regulation. To improve the food qualified percent of the original(new) food manufacturer is a key move to enhance the consumer’s satisfaction, payment willingness and food consumption scale. At the same time, keeping the effectiveness on market, government regulation and information transfer are premise to increase the 4 subjects’ revenue. The food price, the food safety level and consumer’s expected utility have positive correlation between the original food manufacturer and new food manufacturer, in addition, the food price, the food safety level and the food detection accuracy have positive correlation too.