Abstract: In order to investigate the effects of deficit irrigation on maize yield and select irrigation method to save water resource which would be taken in the future, under climate change scenarios, crop model and output data of PRECIS regional climate model in the future period, together with historical observation data, were used in the study. It was designed as a number of irrigation levels to simulate maize growth and analyzed the local crop water productivity and optimal irrigation solutions. The results showed that: in historical period, the amount of water usage for irrigation was more than crop needed, and it was not the rational utilization of water resources; under future climate change scenarios, effects of the different irrigation treatments had no marked differences on maize growth duration, however, yield and biomass had bigger responds to irrigation quantity. Crop water productivity reached its maximum 0.68 and 0.80 respectively under A2, B2 climatic scenario while using 58% of the full amount of irrigation. At the meantime, the maize yield accounted for 77%-82% of the fully irrigated corn yield, and it could save water 2700 m³/hm² compared to fully irrigated treatment. Therefore, the deficit irrigation style would be a scientific and reasonable way to achieve maximum efficiency of irrigation water.