Abstract:Soil erodibility is an important index to measure soil susceptibility to water erosion, and an essential parameter needed for soil erosion evaluation and soil erosion prediction. Based on 1 255 typical soil profile data, the values of soil erodibility(K values) of all the soil types on the Qinghai-Tibet Plateau were calculated by erosion-produtivity impact calculator(EPIC) mathematical model and GIS. On which the weighted averages of the areas with the different values of soil erodibility are derived, and the distribution of the values of soil erodibility is analyzed based on map(1:1 000 000) of soil types in the Qinghai-Tibet Plateau. The results showed that the mean value of soil erodibility was 0.230 8, and the area of lower, less lower, moderate, less higher, higher erodibility soils occupied 5.60%, 18.23%, 24.35%, 44.02% and 7.80% of the Qinghai-Tibet Plateau, respectively.The total area of moderate and less higher erodibility soils is 1.77×106 km2 which is 68.37% of the total research area. The less higher and higher erodibility soils distribute in the Qiangtang Plateau, the Qaidam Basin and the valley of the Hengduan Mountains. Soil erodibility vertical variations are obvious in the Qinghai-Tibet Plateau, and especially in the Hengduan Mountains. Soil erodibility shows a decreasing trend from lower altitude to higher altitude. The physical and chemical properties of soils are affected by the water and the heat condition along an elevational gradient, and then the vertical variations of the physical and chemical properties of soils determine the vertical variations of the soil erodibility.