Global warming and water shortage are important issues in the face of rice sustainable production. A field experiment was conducted to investigate the effects of water saving irrigation on photosynthetic and chlorophyll fluorescence characteristics in rice under nighttime warming. Randomized block design was adopted in the experiment. Night temperature was set two levels,nighttime warming ( NW,nighttime warming) and control ( CK,ambient temperature),and water management was set two levels,traditional flooding irrigation ( F,5 cm water layer) and moistening irrigation ( M,water saving irrigation without water layer). The results showed that the passive warming system increased the nighttime average temperature of the canopy in the whole growth period of rice under traditional flooding irrigation and moistening irrigation by 0.42 ℃ and 1.18 ℃,respectively. Compared with ambient temperature,nighttime warming decreased the SPAD value and maximum net photosynthetic rate of rice,increased the light saturation point,light compensation point,dark respiration rate and fluorescence dissipation,decreased the performance of photosynthetic apparatus,and decreased the dry matter accumulation. In conclusion,under nighttime warming, moistening irrigation increased the net photosynthetic rate and light saturation point in rice,reduced the light compensation point,dark respiration rate and fluorescence dissipation of rice,increased the light adaptation range of rice,enhanced the performance of photosynthetic apparatus,reduced the dry weight of panicles.