Abstract: A field experiment was conducted to investigate the actual impacts of nighttime warming on rice growth stage and grain yield in Danyang, Jiangsu Province, with 8 leading varieties approved and released during 1970s-2000s. The field was warmed at nighttime for an entire growth stage (i.e. sown date to harvest) with a Free Air Temperature Increase (FATI) facility. The results showed that there were significant differences in the extents of warming impact on rice growth stage and grain yield among the leading varieties, though the impact trends were similar. An increase of 0.9 ℃ in nighttime mean temperature in rice canopy could shorten the length of rice entire growth stage by 1.3 d. Nighttime warming tended to decrease postanthesis green leaves area and the flag leaf area, and to decline rice aboveground biomass production and grain yield by 3.5% and 5.1%, respectively. Meanwhile, nighttime warming decreased the plant nitrogen concentration at maturity. Nighttime warming reduced the grain yield mainly through decreasing the effective panicles and grain numbers per panicle. There was no stable changing trend in the differences in warming impacts on the varieties released in the different periods.