The PearsonType Ⅲ and the ExtremeValue TypeⅠ curves are widely used in China and abroad for calculating the maximal wind speeds. Based on the 10minute mean maximum wind speed data of Qianxian and Fufeng (Shanxi Province) from 1972 to 2004, by using the methods of the PearsonType Ⅲ, ExtremeValue TypeⅠcurves, the extreme values of the 10minute mean maximum wind speed for occurring once every 30 and 50 years are estimated. The results show that according to empirical scattering points and the fitting degree of the theoretical curve, the methods of PearsonType Ⅲ and ExtremeValue Type Ⅰ distribution can be used to adjust the calculation parameters repeatedly. Special attention should be paid to the fitting of small probability events to make the fitting of theoretical curve satisfy the needs of users.