Abstract: Meteorologic data and rice yield data were analyzed in Xinyang from 1991 to 2004, and the reason of yield’s decreasing was intense change of sunlight and temperature from July to September, and the rice yield was reduced by 28.28% compared with average of recent five years. Seed setting rate and spikelet number per panicle were the most serious ones affected by meteorologic conditions in all the yield components, which declined 23.71% and 7.82%, but there was not obvious difference for panicle number and grain weight compared with other years’. Yield was affected most strongly by the deficiency of sunlight from flowering stage to the evening of grain filling, and the correlative coefficient reached 0.7011. Rice yield also could be affected by the low temperature and sunlight in tillering stage, high temperature in the evening of booting stage, and low temperature in flowering stage.