The region of sediment rock in Inner Mongolia is the main source of the coarse sediment for the Yellow River, which has the character of the interaction of wind erosion, hydraulic erosion and gravity erosion.Using the natural observation data, we analyzed and got the rules of spatial and temporal distribution of the interaction of wind erosion, hydraulic erosion and gravity erosion. According to the study on the chemical and physical features and the rules of soil erosion and sediment yield for the sediment rock, we got the result: the capabilities of runoff yield and sediment yield are higher than the loess soil and aeolian sandy soil. We built up the hydraulic erosion model and simulated the erosion process of the study region.