Transpiration of Stipa bungeana in Huangfuchuan watershed was measured using isolated weighing method.Synchronous environmental factors such as incident solar radiation,air temperature,relative air humidity,wind speed,and soil temperature at depth of 10cm were recorded continuously using automatic weather station.Leaf transpiration rate and leaf stomatal conductance were also measured using LI-6400.The data were then processed using Excel 2003,Visual C⁺⁺ 6.0,and SPSS 13.0. The individual transpiration model was developed by analyzing the correlation between transpiration and environmental factors along with plant characteristic factors.The model is evaluated to be good based on the performance indices.The mathematical model of daily transpiration for S.bungeana in Huangfuchuan watershed was developed based on the model of hourly transpiration.