In order to clarify the high and stable yield mechanism of Bainong 207, the photosynthetic characteristics,dry matter dynamics, and yield characteristics of Bainong 207, Zhoumai 18, and Aikang 58 were studied under natural field conditions. The results showed that Bainong 207 had higher photosynthetic characteristics, and the photosynthetic rate of anthesis stage was the highest, which was 15.76% and 18.22% higher than that of Zhoumai 18 and Aikang 58, respectively. It could maintain high photosynthetic rate for a long time after anthesis. The weight of single stem was heaviest in all growth periods. It was found that Bainong 207 was a typical tillering type with general tillering ability and high heading rate. According to yield and character analysis, grain number per ear and grain weight per ear of Bainong 207 increased significantly, and its economic yield was 2.48% and 14.50% higher than that of Zhoumai 18 and Aikang 58, respectively. High photosynthetic rate, more dry matter accumulation, high panicle rate and the increase of grain number per spike and grain weight per spike are the physiological basis for high and stable yield of Bainong 207.