Based on the rule of wind friction decomposition on the rough wall in the turbulent boundary layer,threshold velocity of soil erosion,sand transport rate and wind erosion rate were studied to explore effect of roughn essele ments on soilwind erosion,and thus a soil erosion theory was derived,from which some theoretical results were developed that the exponential relation between threshold velocity and coverage,the exponential relation between threshold velocity and stubble height for farm lands after harvesting,and the theoretical formulas of the effect of wind velocity and coverage(or stubble height) on sand tran sportrate and wind erosion rate.They were applied to and verified in a series of experiments on wind erosion of natural land and farmland,and found to be extensively applicable.