An optimization model for yield and fertilizer efficiency was established by many years and sites experimentation of N and P fertilizer combination for maize production in black soil region. The results showed that the optimum rate of N applied was 172.9kg/ha, that of P₂O₅ was 57.4kg/ha, and the optimum N:P₂O₅ ratio was 3:1, which could win an optimum yield of 7791.0 kg/ha. Within the range of optimum rate of fertilizer application 14.4kg and 16.9kg of maize yields could be increased by each kg of N and P separately when the applied amounts of N and P were equal. The efficiency of phosphorus fertilizer was better than that of nitrogen fertilizer, but the yield-increasing potential of N was far higher than that of P.734.9kg/ha of maize yield could be increased if only phosphorus fertilizer was applied, but 1597.9kg/ha of the yield could be increased when only nitrogen fertilizer was applied. Under the condition of optimum fertilizer application, N fertilizer's efficiency was 23.8-37.1%,and P fertilizer's efficiency was 14.2-22.2%. 68.9% of maize yield was dependent upon the soil.