Abstract: Based on open-source Nek5000, a grid generation method of SEM (Spectral Element Method) for complex terrain was put forward, and the wind field of Askervein hill was numerically simulated by LES (Large-eddy-simulation). The result of numerical simulation was compared with the field observation and another numerical result. The comparisons show that the wind speed acceleration factor on line-A obtained by LES simulation is in good agreement with the results from the field observation. SEM combined with LES turbulence model can be used to predict wind energy resource distribution on complex terrain.