Based on the meteorological tower data obtained from Jiangsu and Jilin in 2005-2 006, the characteristics of average wind profile are analyzed， and a new method for estimating mean wind energy density in different height is investigated. Th e results show that the average relative error of this method is 4.4%， while th e largest relative error is 13.3%, so this method for estimating the variation o f wind energy with height is usable.