Abstract:The field trials were conducted in south Ningxia province by using regression design of gerneral rotation. By means of establishing mathematical model，the relationship among N,P2o5，M and yield was analysised. In addition,a system of optimum model of fertilizing N,P,and M were obtained，with which the output would be above 3 OOOkg/ha in terrace and 2400kg/ha in tableland. Also，the limited line of fertilizer input were given:N 100.5kg/ha,P2o5105.0kg/ha,M 30 000kg/ha in terraces and N 110. 0kg/ha,P2o5,105. 0kg/ha，M 30 000kg/ha in tableland. Those results could be used in practice to improve yield,save fertilizer and to fore-cast yield.