Abstract: ‘Qingmai 6’ and ‘Jimai 22’ were used as the experimental materials to study the effect on photosynthetic characteristics and yield of wheat flag leaves under different concentrations of salt stress, with ordinary soil as control. The results showed that different salt-tolerant wheat varieties presented different responses to salt stress. The chlorophyll content, leaf area index, net photosynthetic rate, stomatal conductance, and transpiration rate of ‘Jimai 22’ declined dramatically. In contrast, these indicators fall much more slowly in ‘Qingmai 6’. Furthermore, the CO₂ concentration between cells of‘Qingmai 6’ increased less compared with ‘Jimai 22’. Compared with that of the control, the ear number per unit, kernel number per spike and 1000-grain weight of the two wheat varieties reduced under salt stress. The increase amplitude aggravated with the increase of salt concentration levels. But the decrease of yield was moderate in ‘Qingmai 6’. The key to gain high and stable yield for ‘Qingmai 6’ which kept higher photosynthetic characteristics was the ear number per unit under salt stress. This study provided a theoretical reference for wheat cultivation in saline-alkali soil with different degrees of salt.