In the light of the principle of optimal simulation analysis of systematic engineering,adopting the method
of orthogonal combination design of quadratic regression,the optimization combination of cultivating practices of high yield and high benefit for cropping
autumn soybean after double cropping of rice and wheat were studied. The main
controllable factors such as the date of cultivating seedling, cultivating density and amount of fertilizer applied were included under the ecological condition of Sichuan province. The two mathematical models of high yield and high benefit have been set up. The squence of decision variables of 3 controllable factors and the relation of the variables with the highest yield and the optimal benefit had been made clear. The optimal technological combination with the yield of soybean of 100～125 kg/667m 2 and above 125 kg/667m 2 and the net output value above 400 RMB$/667m 2 have been gotten.