In order to reveal the change in photosynthetic characteristics and responsive mechanisms of different leaf positions in watersaving droughtresistant rice and highyield rice under watersaving irrigation,watersaving and droughtresistant rice Hanyou113 (HY113) and highyield rice Yangliangyou 6 (YLY6) were used to conduct a pot experiment in 2015.The effects of traditional flooding (F),saturated treatment (S) and drought treatment (D) on the leaf water potential,SPAD values,leaf gas exchange,instantaneous water use efficiency of function leaf at four important growth stages including jointing stage,booting stage,heading stage and milky stage and yield of rice varieties were studied.The results showed that the yield of YLY6 in S treatment was significantly increased compared with other treatments,contributed by higher effective panicles,grains per panicle and filled grains rate.Correlation analyses showed that there was a significant positive correlation between dry matter accumulation and yield heading stage and milky stage,and a significant positive correlation between net photosynthetic rate at the booting stage and heading stage and the dry matter quality at heading stage and milky stages.The dry matter accumulation of YLY6 at booting stage,heading stage and milky stage under saturated treatment was significantly higher than that of HY113.The instantaneous water use efficiency of YLY6 at heading stage was significantly higher than that of HY113.Under S treatment,YLY6 maintained high net photosynthetic rate with high SPAD value,stomatal conductance,and transpiration rate at the postfertility stage (from milky stage to mature stage) to maintain a high photosynthetic productive potential.Therefore,YLY6 maintains high photosynthetic capacity in different leaf positions at the late growth stage (milky period) under S treatment,which is the basis for watersaving and highyield rice.