Soil erosion process research produces the knowledge and science used in the development of current process based erosion prediction model. This presentation will highlight past efforts in deve loping erosion process concepts that lead to the development of current process-based erosion prediction model, i.e., WEPP. Recent erosion process studies have produced data sets that challenge some of the WEPP model concepts. We hope erosion process and model research in USA could enhance soil erosion research in China.