A experiment usingZhengdan 958(a summer maize cultivar planted widely in China),with treatments of three water levels(normal water W3,mild water stress W2,severe water stress W1)and four amounts of controlled release urea nitrogen(N)(N3 was 300 kg ha-1,N2 was 225 kg ha-1,N1 was 150 kg ha-1 and N0 was no nitrogen)was carried out under the waterproof shed and soil-column conditions.The results showed that the coupling of water and controlled release urea had significant effects on improving yield,delaying the leaf senescence and improving the efficiency and time of the functional leaves.Under the same nitrogen condition,yield,LAI,chlorophyll content and the activities of SOD,POD and CAT in summer maize ear leaf were significantly increased with the increase of moisture content,soluble protein content increased and the content of MAD reduced significantly.Under the condition of same water,these indicators were also significantly increased with the increased amount of nitrogen application and MDA content reduced significantly.However,the treatments of W3N3,W3N2 and W2N3 had no significant differences and compared to other treatments,the indicators(except MAD)were maintained at a high level,the MAD content was low,which showed that the coupling of water and controlled release urea had an important role on maintaining the function of ear leaf,delaying the leaf senescence,promoting the production of photosynthetic products and improving the yield of summer maize.Integrated the expression of yield,LAI,chlorophyll content,various protective enzymes activity,MDA and soluble protein,controlled release urea N application rate of 225 kg ha-1 was the best treatment as the soil moisture content was 75%±5%of field capacity and continued application of nitrogen fertilizer could not increase the protective enzymes activity and lead to the activity of protective enzymes decreased and MDA content increased rapidly,thereby speed up plants translation to senescence,which is not conducive to the efficient use of nitrogen.We suggested that coupling controlled release urea N application rate of 300 kg ha-1 with soil moisture content of 55%±5%of field capacity is optimum.