The strong wind fields a wind farm were simulated numerically during Typhoon Melor passed by in 2009. The mesoscale model, WRF-ARW (http://wrf-model.org/index.php) was used for the large scale calculation domain. The simulated wind fields were used for the inlet boundary conditions of the smaller calculation domain with fine meshes around the wind farm. The unsteady wind fields were calculated by Large Eddy Simulation (LES). The calculated results showed good correlation with the observed records of wind speeds and directions. They reproduced large scale fluctuations of wind speed and directions originated from the upwind geographical features.