On the basis of the analysis of the erosion and sediment yield mechanism of hill slope-gully surface erosion system by physical model experiments, the basic theories of erosion dynamics, hydrology and sediment transport mechanics, the distributed soil loss model and support system for complex erosion environments were developed by GIS in the rich and coarse sediment area of the Yellow River basin. The coupling relation of erosion and sediment yield of hill slope-gully side erosion system under vegetation effects was disclosed. The conception of “ equivalent roughness ” was put forwarded. The distributed hydrodynamic model for soil erosion based on GIS was established, which close couples the GIS, soil loss model, runoff produced model, sediment yield and transport model. Also, the support system based on ArcGIS was developed. By two illustrations, the simulated results obtained using this model for larger water bain soil loss were examined.