In order to solve the problem of low accuracy in wind energy resource assessment, this paper uses NCEP data to extract meteorological data of wind farms, and uses STRM data to obtain macroscopic topography of wind farms. With the support of WAsP software, the key indicators of wind energy resources such as wind speed and wind power density are then calculated. After knowing these indicators of the distribution of wind energy resources, the Weibull distribution of the two parameters are obtained. Then the frequency distribution of wind speed are simulated and the power generation are estimated. The proposed method provides a theoretical basis for the construction of wind farms and guidance for the precise positioning of the wind farms in the later period. Finally, an example is included to verify that the proposed method is feasible, effective and has high prediction accuracy.