Effect of different water and nitrogen supply on yield and agronomic characters of maize was studied under controllable rain-protected shed.The results showed that low nitrogen stress increased yield of maize compared with control under water stress condition.While low nitrogen stress decreased yield of maize under sufficient water condition,but not significantly.Nitrogen fertilizer increased plant height and leaf area under sufficient water condition.Effect of water on dry matter accumulation was higher than that of nitrogen.Nitrogen promoted absorption of soil water in root,and the root grew well under proper drought condition.The root system aged seriously under combined stress of drought and nitrogen.