Abstract: Based on the observation of the sap flow flux of Hippophae rhamnoides by the stem heat balance method on northern slope of Liupan Mountains, this paper analyzed the daily sap flow characteristics of H. rhamnoides during the growing season, and estimated the transpiration of H. rhamnoides plantations. The curve of daily sap low showed a typical single-peak pattern, and indicated that sap flow continued till night. The ratio of nocturnal sap flow flux to total daily sap flow flux is about 12.87% to 19.62%. The daily sap flow flux could be affected by total daily solar radiation, mean vapor pressure deficit, mean air temperature and mean relative air humidity. The transpiration velocity of H. rhamnoides showed an obvious declining trend from March to September, with a total transpiration of 469.4 mm, which was a little higher than the simultaneous precipitation, and the ratio of this transpiration to simultaneous total evapotranspiration is 35.11%. The regression equation to relate environmental parameters to total transpiration was established.