Abstract: The data of hydrology and meteorology for the recent 40 years were used to analyze the influence of climate warming during 1980s~1990s and human activity on the relationship between precipitation and runoff for middle-small rivers of northern Xinjiang.Main conclusions are as follows:(1) The relationship between natural precipitation and runoff of Halayimiele river and Kalangguer river located in the west of northern Xinjiang had no distinct change under the background of climate warming after 1980.(2) The relationship between natural precipitation and runoff of Daqing river located in the east of Erqisi river basin in northern Xinjiang,whose runoff-producing area has higher mean elevation,also had no distinct change under the background of climate warming during 1990s;but the relationship of Xiaoqing river located in the east of Daqinng river,which has lower mean elevation of runoff-producing area and little mountainous area precipitation,changed and the natural surface runoff decreased clearly under the background of climate warming during 1990s.(3) The relationship between natural precipitation and runoff of Urumqi river located in the north slope of middle Tianshan mountains in Northern Xinjiang also changed,and the natural surface runoff increased distinctly under the background of climate warming during 1980s~1990s in Northern Xinjiang.(4) The relationship between natural precipitation and runoff of Kaiken river located in the north of eastern Tianshan mountains changed and the natural surface runoff decreased under the background of climate warming during 1980s~1990s and influence of human activity.(5) The relationship between natural precipitation and runoff of Shuimo river located in the low mountain and hilly land of Urumqi outskirts also changed,and the runoff decreased under the background of climate warming for the recent 40 years and influence of human activity in spite of annual precipitation at Urumqi has increasing trend.

Key words: climate warming, human activity, the northern Xinjiang, middle and small river, relationship between precipitation and runoff