The upper reaches of the Heihe river basin is the vital ecological function region of water conservation,which is of great significance to maintain the ecological balance of the whole basin.A water yield model based on InVEST was employed to estimates water conservation in the upper reaches of Heihe River basin.this paper analyzes the spatial and temporal characteristics of water conservation and the correlation between water conservation and climate factors.The main conclusions are as follows:(1) The area of grass,scrub and woodland increased by 1 665 km~2,381.75 km~2 and 162.75 km~2,respectively in the upper reaches of Heihe river basin from 2001 to 2015.By contrast,deserts and farmland were reduced by 2 165.25 km~2 and 20.5 km~2,respectively;The year mean value of water conservation was 228.64 mm and the spatial distribution of water conservation was high southeast,low northwest in the upper reaches of the Heihe River basin in 2001-2015.The higher value area is located in the Qilian Mountains area,northern Sunan Yugur Autonomous County banded high value area upstream water conservation,in 2008 and later,water conservation is lower than the basic anomaly.Overall,water conservation showed a decreasing trend at the annual rate of 7.60 mm;In the past 15 years,the variation of potential evapotranspiration and precipitation has been the main climatic factor affecting the change of water conservation in the study area.The potential evapotranspiration and precipitation showed a trend of increase and decrease respectively in the upper reaches of Heihe River basin.The rates were 1.45 mm·a~(-1) and-0.67 mm·a~(-1) respectively.The water conservation was negatively correlated with potential evapotranspiration and precipitation is positively correlated.Precipitation mainly affects the Middle East,north of Qilian Mountains alpine region while potential evapotranspiration mainly restricts the water resources in the northwest.