Abstract: The experiment was conducted at YuCheng Comprehensive Experimental Station to study the effect of different soil moisture before sowing on physiologic character and yield of summer maize. The experiment showed that in the condition of very droughty, the treatment which irrigated at jointing and heading stage in growth period of wheat and 100mm water in growth period of summer maize gained maize kernel 7466.58kg/hm2. The leaf area, photosynthetic rate and transpiration rate of the treatment were much higher than the others, but stomata resistance and leaf temperature were much lower. The variety of above physiologic index were caused by irrigation in growth period of winter wheat, so caused the difference of soil moisture before sowing. Because the difference of soil moisture before sowing, the yield of every treatment were also different. The experiment also showed study water problems of crops should be combined with specific planting system.