Abstract: Based on the monthly precipitation and temperature data of Yunnan's 122 stations from 1961 to 2006, the utilizable precipitation was calculated by means of Takahashi's evaporation equation. Its evolutional characteristics under the background of the global climate warming were analyzed by using the methods of regression analysis. The results indicate that the utilizable precipitation decreased in summer, autumn and winter season, especially in summer, so that annual utilizable precipitation also obviously reduced in the past nearly 50 years over Yunnan Province. The seasonal and annual utilizable precipitation all showed distinctively interannual and interdecadal oscillations except the winter utilizable precipitation which only displayed interannual variations. Regionally, winter and spring utilizable precipitation increased, and summer one reduced in most of Yunnan Province, and autumn utilizable precipitation reduced in the eastern but increased in the western of Yunnan Province; and annual utilizable precipitation reduced in the eastern and southern of Yunnan Province, but mainly increased in the rest areas. When the global climate was warmer, annual utilizable precipitation was lesser in most of Yunnan Province and vice versa.

Key words: Yunnan utiYunnan Province, utilizable precipitation, the temporal and spatial distribution, regressive analysis