In order to reveal different region temperature and precipitation of climate change tendency and unit area grain yield influence in Anhui Province, based on meteorological data from 1971 to 1990 and unit area grain yield from 1991 to 2010 in 78 counties Anhui Province. On the background of climate changes in Anhui Province, the author analyzed the effect of precipitation on grain yield by adopting mathematical statistics. The results showed that; temperature rose obviously, but inter-annual variation was relatively small. Precipitation had no significant trend variation, but the inter-annual fluctuation was large. The northern precipitation was less than the south, but the variation coefficient was greater than the south. So output fluctuation was mainly caused by unstable water condition. From March to September optimum precipitation in positive growth phase, which 4 region crops was respectively to 400-800, 400-1000, 500-1000, 800-1400 mm from north to south. Actively growing period crops and precipitation were bullish which were synchronal. Precipitation was bullish that was produced adverse effected by output, especially of 4 regions.