Series of soil and water loss (SWL) problems, such as landslip, debris flow, and collapse, occurred due to “ 5.12 Wenchuan earthquake ” , which were characterized by high disturbance, extensive influence, and big destruction. The severe SWL had seriously threatened the sustainable development of society and environment in the earthquake area. On the basis of this, by adopting statistics method, this paper analyzes the soil loss change before and after Wenchuan earthquake. The results show that: the mild SWL area of farmland, grassland and forest ecosystem in the heavy earthquake area presents decrease tendency after earthquake, and moderate and severe SWL have increase tendency. After earthquake there exists dynamic transformation in different SWL grades, and mild SWL would change into moderate and severe SWL. Compared with the change of SWL area in earthquake area, after earthquake, the degree and intensity of SWL in the heavy earthquake area have a distinct increase.