Kobresia pygmaea, a dominant species of alpine meadows in Qinghai-Tibet Plateau, was selected to measure the diurnal variation of stomatal gas exchange parameters and environmental factors with a portable photosynthesis system from July to September, 2018. The soil water parameters at 0-10 cm layer were measured also with soil moisture meters, ring knife method, and permeable membrane method. Then, the parameters of three stomatal conductance models, Jarvis's model, Leung's model, and Gao's model, were applied to simulate the stomatal conductance of Kobresia pygmaea, after the calibration of their parameters based on the measurements in different months of July, August, and September. It was also analyzed based on the simulation that the response characteristics of stomatal conductance to the main environmental factors such as Photosynthetically Active Radiation (PAR), air temperature (T_air) and Vapor Pressure Deficit (VPD). The main results are as follows: (1) all the three models could well simulate the changes of the stomatal conductance of Kobresia pygmaea, with the performance sequence of Leuning's model (R²=0.726), Jarvis's model (R²=0.659), and Gao's model (R²=0.624). (2) The sensitivity of stomatal conductance of Kobresia pygmaea to the three environmental factors occurred in the order of PAR > VPD > T_air. The stomatal conductance showed a bell-shaped response to T_air ranged of 5-35 ℃, with the maximum value at 24.83 ℃. The stomatal conductance also had a maximum value at PAR of 2100 μmol m^-2 s^-1, but monotonically decreased with VPD ranged of 0.12-3.48 kPa. (3) All the three models could well simulate the response characteristics of the stomatal conductance of Kobresia pygmaea to the environmental factors, with the highest sensitivity to VPD. Among the three models, Leuning's model was most sensitive to T_air and VPD, and Gao's model was most sensitive to PAR, but lest sensitive to T_air. The purpose of this study is to provide a reference for understanding the response of stomatal conductance of plant on Qinghai-Tibet Plateau to climate change, and for the application of stomatal conductance models in larger-scale land surface models.