Abstract: At present, it has been found that the reduction in production occurring in the high-yielded wheat plots is caused by the excessive utilization of nitrogen fertilizer and high frequency of irrigation. The effects of different nitrogens and water levels on wheat yield are discussed and a mathematical model is described in the paper. Based on the overall evaluation of input and output, the optimum requirements for the nitrogen amount and irrigation frequency are found out, thus bringing the great help to raise nitrogen and water efficiency to wheat.