Abstract: Using quadratic regression universal rotary combination design, we studied relations between grain yield of Qian-bitter-buckwheat 2 which was planted in spring and four main agronomic measures（seeding rate, N-application rate , P2O5-application rate and K2O-application rate）.Mathematics model was set up by experiment．By simulating the model and simulation-optimization analysis，we put forward cultivation techniques programme（buckwheat grain yield≥2800kg/hm²）: seeding rate is 67.14~74.39 kg/hm², N-application rate is 28.88~40.12kg/hm2, P₂O₅-application rate is 179.11~210.89kg/hm², K2O-application rate is 43.94~61.06 kg/hm². The results showed that the effect on grain yield is：seeding rate＞K₂O-application rate＞P₂O₅-application rate＞N-application rate.