Soil wind erosion refers to the process of loose soil substances being blown up and carried away by wind and de posited somewhere else,and the process of land surface being abraded by the blown up soil particles.Its essential is the process of fine soil particles and nutrient matters in the surface soil being blown away by wind.In China the total area of lands exposed to wind erosion and desertification exceeds one half of its total land area.Those lands are distributed mainly in the arid and semi arid regions in North China.The Hexi Corridor in Gansu Province is one of the areas that are subjected to most serious desertifi cation,because of its long term conventional tillage and prevalence of northwester.A wind tunnel experiment was designed to study effects of conservative tillage in winter wheat cultivation on wind blown mass,critical wind speed,wind velocity profile and roughness of land surface and their relationships.Results show that all the treatments were higher than CK (SWT,spring wheat with conventional tillage) in wind blown mass and critical wind speed.Wind blown mass showed a power function relationship with wind speed and the wind speed of 16 ms^-1 was the turning point from slight wind erosion to serious wind erosion.Within the height of 5~50 mm above the land surface,the rise of wind velocity with height in Treatment NTS (no tillage with stubble retention (NTS) and Treatment NT (no tillage with no stubble) was slower than in Treatment TIS (conventional tillage with stub ble incorporated) and Treatment T (conventional tillage),and height and wind speed formed an exponential function in all the treatments.Roughness of the land surface varied significantly between Treatments NT,NTS and SWT at 0.01 level,but it did not between Treatments TIS and SWT.Significant negative relationship was observed between wind speed and roughness,and al so between crit ical wind speed and roughness.