Abstract: With the development of wind power utilization systems, an increasing number of wind farms are built in complex terrains such as mountainous areas. For better wind energy assessment and wind power forecast, understanding the impacts of complex terrains on the wind speed profile is necessary. Based on the thin airfoil theory and the linearization theory of the disturbance of the turbulent boundary layer, this paper predicts the wind speed profile in the two-dimensional cross section using a two-layer model. The model can accurately predict the influences of terrain, pressure, and stability on wind speed. However, for three-dimensional terrains or other factors, the model needs to be further extended to three dimensions and combined with numerical simulations.