Abstract: Xianyu335 and Jundan8 as materials, four row spacing (70, 65, 60,and 55 cm) were used in this study. We measured leaf area index, photosynthetic rate, chlorophyll content and soluble protein content in late growth stage. The results showed that: compared with other treatments, LAI, physical activity and photosynthetic rate were higher, and chlorophyll content and soluble protein content were both maintained at high level in 50 and 70 cm row spacing. 70 and 50cm row spacing with a greater potential for photosynthetic production is conducive to high yield than the 65and 60 cm spacing.