Abstract: Using the daily precipitation data（20：00-20：00） from May to September in 1976-2016 of 7 national automatic weather stations in Jiuquan, located in the west of the Hexi Corridor, using statistical methods, the spatial-temporal distribution characteristics and trends of rainy days, precipitation, and extreme precipitation events in Jiuquan were studied. The results show that Jiuquan has the most mild rainy days, accounting for 82.1% of the total rainy days. Nearly 1/3 of the rainfall in May-September is provided by mild rain, and 2/3 are provided by precipitation above moderate rain. The spatial distribution characteristics of rainy days （quantities） at all levels are： the most is Subei, the least is Dunhuang. Meanwhile, the absolute intensity of Jiuquan extreme precipitation events in the past 41 years is relatively small and the relative intensity is large. There is no significant linear trend in the frequency of heavy rainfall events, and it has remained stable at about 0.1 times per year. However, its inter-annual and inter-decadal fluctuations are very obvious. The time distribution of no rainstorm events is relatively scattered, and it occurs in every age. In addition, there were no extreme precipitation events in August-September 2011-2016.

Key words: rainy day, graded precipitation, effective precipitation, extreme precipitation, western Hexi Corridor