Abstract: Based on the change of the reference crop evapotranspiration and crop water requirement during development stage of maize in recent 26 years in three provinces of Northeast China, combined with the climate change scenario A2 (concentration on the economic development) and B2 (concentration on the sustainable development) of Special Report on Emissions Scenarios (SRES), the change trend of impact of future climate change on maize water requirement was studied. Results showed that there would be a significant increasing trend in anomaly percentage of maize water requirement under climate change in most sites in three provinces of Northeast China, the increased amount would even be about 77.8% at most, and the spatial distribution of water requirement was different under different geographical and climatic environment. Under A2 scenario, anomaly percentage of maize water requirement might increase by about 27.2% by 2040, about 34.5% by 2070 and 42.9% by 2100; Under B2 scenario, anomaly percentage of maize water requirement might also increase by about 28.6% by 2040, about 33.3% by 2070 and 37.3% by 2100. So there will be a tendency of water resource deficiency in three provinces of Northeast China in the future.