Abstract: The numerical simulations on wind field structure of two real islands under strong wind conditions are made. The results show that the island topography has obvious effects on island wind observations, it is unreasonable to make altitude reduction in order to obtain the wind data at 10 m above sea level by exponential or logarithmic profile formula. The simulated values are compared to the island wind observations, from which it is shown that there is necessity and possibility to seek for an approach to correct island strong wind data with numerical simulation.