Abstract: The paper aims to better develop and use climate resources, reasonably guide the production of various industries and scientifically use water resources and protect ecological environment. Using daily precipitation data of 5 meteorological stations in Wuwei City during 1961-2013, space-time distribution characteristics on rain days were systematically analyzed with linear trend coefficient method. The result showed that: space distributions of annual and various magnitudes rain days had a trend of decreasing from the southwest to the northeast in Wuwei City. Monthly variation of rain days was more consistent, one obvious peak was in July and one obvious trough was in November to December. Rain days of various regions of Wuwei except Gulang had a decreasing trend in all four seasons. Rain days of the year and time also had a decreasing trend, time series of annual rain days had 4-5 years quasi-periodic variation. Light rain was the main form of precipitation in Wuwei City, and it probability was 92.7% to 96.9% of the total rain days. Rain days decreased rapidly with the increasing of rainfall magnitude. Light rain days of rainfall 0.0 mm all had a decreasing trend. Variation trends of light rain days of rainfall more than 0.0 mm and rain days of rainfall over 10.0 mm were inconsistent in the whole city and various regions.