Buon Yong catchment covers the areas of Cu Mgar and Krong Buk districts in Vietnam. Its average elevation is 550 m, and the surface area is 10, 365 hectares. The terrain is mountainous with various slopes and separated by many water courses and valleys. The annual average rainfall here is rather. Therefore erosion caused by rainfall is unavoidable in this catchment. The survey showed that, erosion took place strongly in Buon Yong catchment, especially at the places of annual crops, young rubber or coffee planted without good anti-erosive measures. Even though, at the sites of old coffee where the soils were not well protected, the run off and soil loss were also quite high. The erosion also depended on soil slopes and cultivated practices, which were difference in this area, therefore the data of soil loss and run off collected at the sites were various. The methods of soil protection as planting contour-hedgerows, making basin reduced run off and soil loss remarkably.