Based on soil hydrothermal and meteorological data of the Tanggula area of the Yangtze River source from 2020 to 2021, SHAW model was used to simulate soil temperature and moisture to calculate the characteristics of soil water balance and surface energy balance. The results showed that, 1) the simulation effect of soil temperature was better than that of soil moisture, nash efficiency coefficient (NSE) was > 0.93 and R²> 0.97 for temperature simulation, while the mean NSE and R²were>0.61 and >0.79 for soil moisture simulation, respectively, indicating that the simulation results were reliable. 2)The components of water balance all showed obvious variation characteristics of cold and warm seasons. The precipitation and the deep upward recharge accounted for 86.4% and 13.6% of water income, while deep seepage, evapotranspiration, soil water storage and surface water accumulation accounted for 36%, 49.1%, 14.4% and 0.5% of water expenditure, respectively. 3) The surface energy balance changed alternately in the cold and warm seasons, the net radiation, latent heat flux and soil heat flux increased in the warm season and decreased in the cold season, and the sensible heat flux showed an opposite trend, and the monsoon activity and freeze-thaw action were the key factors affecting the net radiation budget. During the simulation period, the average daily net radiation was 46.48 W/m², of which 32.7% was converted into sensible heat flux, 65.1% converted into latent heat flux, and soil heat flux accounted for only 0.3%.