Abstract: In this paper, the various trends and distributional characteristics of precipitation in the Qilian Mountains were studied using the data of hourly and daily precipitation in the mountains. Moreover, the tree-ring data of Picea asperata growing in the study area were used to analyze the response of tree-ring width to precipitation in the mountainous. A unitary linear regression model was used to develop a transfer equation so as to reveal the relationships between the standardized chronology of tree-ring width and the average precipitation at Minle Meteorological Station during the period from August to next July and the change of annual precipitation in recent 200 years. The results show that precipitation in 19^th century was higher than that in 20^th century. Drought occurred increasingly in 20^th century, especially severe drought occurred in the 1920s and 1930s, such trend was consistent with that in north China. Precipitation in the Qilian Mountains was closely related to the altitude, and most precipitation occurred in the afternoon and nighttime. Flood season in the study area is in July and August. Moreover, the frequency of extreme precipitation was increased in recent decades, and the change of annual precipitation was not significant.

Key words: precipitation variability, climate change, tree-ring, altitude, precipitation series, Qilian Mountains