Abstract: Based on the mesoscale meteorological model, the subgrid-scale terrain parameterization scheme was used to simulate a gale weather in Baihetan Hydropower Station, which lied in the junction of Sichuan and Yunnan province, from March 19 to 20, 2019. The simulation results of spatial distribution and diurnal variation of 10m wind speed, wind direction and 2m temperature were evaluated, and the causes of this gale were analyzed in combination with the terrain. The results were as follows: The southwest gale weather was caused by the southwest airflow consistent with the surface circulation situation of 'east high and west low'. In the afternoon, the heat low developed strongly, the surface wind speed increased, and there was a strong wind of level 8. After adopting the subgrid-scale terrain parameterization scheme, the MAE and RMSE of the wind speed could be reduced by up to 17 % and 14 %, respectively. Meanwhile, this scheme effectively alleviated the underestimation of the wind speed in the daytime and the overestimation in the nighttime, and could simulate the strong wind and light wind well, so as to capture the diurnal variation of the wind field better. In general, the subgrid-scale terrain scheme could significantly improve the simulation of the wind field, and the Jiménez scheme was more suitable for the simulation of strong wind in the dam area, but the subgrid-scale terrain scheme could not improve the simulation of temperature. The strong wind of Baihetan Hydropower Station was greatly affected by the local terrain. The “narrow pipe effect” caused by the narrow and long valley terrain in the north-south direction increased the wind speed significantly, and when the amplification factor of the valley wind at the main height of the dam area exceeded 3.0, the disastrous gale weather was prone to appear in Baihetan Hydropower Station.