Considering the reasonable cost sharing and fair distribution of profits are the important segments which can affect the system stability of dairy product supply chain and quality assurance. Focusing on a three-tier supply chain consisting of a dairy processing company, a dairy farmer (grazing farm) and a retailer, a differential game method is introduced. The optimal quality management efforts of dairy processors, dairy farmers, and retailers, and their optimal revenue function and the optimal total revenue function of the entire dairy supply chain in four different dairy product quality management game scenarios are analyzed. The research results show that as for dairy processing company, the effort level of quality control and quality improvement are of the uniform expression under the three kinds of non-cooperative quality management circumstances. While under the cooperative quality management game circumstance, considering the total profit of supply chain, the dairy processors which is as the core company change the work effort level of quality management. As to the dairy farmers and retailers which are receptively at the upriver and downriver of supply chain, the work effort level of quality management is improving continually with the cooperative intensification of dairy supply chain. Moreover, this effort may reach the highest level at the ideal cooperative quality management game circumstance.