The optimization and evolution of longitudinal cooperation of Chinese agricultural industry chain can help realize industry chain integration and promote the establishment of benefit complementary mechanism of industry chains.Based on the ways of operation and advantages and disadvantages of many kinds of longitudinal cooperative modes such as market transactions,contracts,cooperative and vertical integration,this paper analyzes the optimization of longitudinal cooperation by building contract game model.The result shows that contract mode is not a steady state longitudinal mode of cooperation,the cooperative mode is the improvement of contract mode and a more effective longitudinal cooperation mode.Therefore,this paper puts forward some relevant policy suggestions on how to promote the vertical cooperation mode in the development of agricultural industry chain.