The DSSAT crop growth model was applied to estimate the summer maize potential photo-temperature productivity and photo-temperate-precipitation productivity, based on a database containing weather, soil, crop varieties, and field trial information from Mengjin in Luoyang. The potential productivity development status as well as the development approach was analyzed. The results show that the range of photo-temperature productivity of summer maize was 6900.00-15805.00 kg?hm-2, and the mean 12039.96 kg?hm-2, which can be used as reference value of average maximum yield in irrigated fields. The range of photo-temperate-precipitation productivity was 1529.31-13742.00 kg?hm-2, and the mean 8894.42 kg?hm-2, which accounted for a photo-temperature productivity of 82%, and can be used as the reference value of average maximum yield in rainfed fields. The average precipitation was 356.22 mm during the summer maize development period, with large annual fluctuations. The water content ratio was 71.9%. Due to different soil types and rainfall years, the range of summer maize potential water use efficiency was 8.04-37.46 kg?hm-2? mm-1; the mean was 26.424 kg?hm-2?mm-1 for 47 years. During the past eight years, summer maize actual water use efficiency only accounted for 45.87% of the potential water use efficiency, and the average development degree of potential photo-temperate-precipitation productivity was 47.55%. The investigation showed that the water-saving potential of summer maize is very large. In the future, it is quite important to use water-saving agriculture measures reasonably and precipitation resources efficiently, to improve the field environment, enhance the stability of the soil water storage capacity, so as to increase water use efficiency and summer maize production.