Abstract: Precipitation and temperature are the most sensitive on formation of the regional climate change because runoff from precipitation，and the form of precipitation （rain and snowfall） and snow melting and freezing and thawing of permafrost phenomena are closely related with the temperature，but the research of watershed runoff is less in Qilian Mountains. There is difficult for constructing measuring weir in Dayekou Basin of Qilian Mountains because river is very big，and difficult for observation rivers runoff ，which obstructed the development of research on function of water conservation in multi-scale basin. In this paper，using the hydrologic observation data in Dayekou Basin of Qilian Mountains for more than 30 years，and combining with the long-term monitoring stations around the reservoir，have carried out the research on characteristics of temperature，precipitation and runoff. The precipitation and temperature and watershed river runoff are long-term monitored and researched during 18 years （1994-2011）. Using parameter calculation，regression analysis，linear tendency analysis，percentage of qualifying for the data processing and analysis，the results show as follows：（1） From the parameter calculation，the annual variation of the temperature is the largest，and river runoff takes second place，and precipitation is the minimum; Annual average temperature，annual precipitation and the annual river runoff are changed from 1.16 to 2.08 ℃，from 307.43 to 440.69 mm，from 129.04 204.42 mm and their probability accounted for 68%. The annual river runoff accounted for 44.57% of the annual precipitation. （2） From the regression model calculation，if the annual average temperature 1.62 ℃，and the annual precipitation is 374.06 mm，the river runoff of estimate is 165.47 mm. （3） From linear tendency analysis，temperature，precipitation and river runoff all showed a trend of volatility rising，including the trend of average rate of temperature is 0.23 ℃·（10 a）^-1，and the precipitation and river runoff are all around 18 mm·（10 a）^-1. （4） From the correlation function，temperature，precipitation and river runoff respectively are 11.91 ℃，2.74 mm and 0.32 mm which are minimum in January. The largest average respectively are 14.38 ℃，82.48 mm and 37.48 mm in July. This research would be provided reference and scientific basis to further reveal the function of water conservation and its producing mechanism in moderate scale basin. This research would be basic work for sustainable exploiting and utilizing water resources in future ，and great significance on perceiving evolving law of hydrological processes in a particular area，and ensuring water resources rational development in the continental river basin，maintaining agricultural sustainable development in Hexi region.

Key words: Temperature, Precipitation, River runoff, Dayekou basin of Qilian Mountains