Northwest Yunnan province is an area of high mountainous and deep valley. The region also contains protected areas of natural forests in the upper reaches of Yangtze river and provides an ecological barrier between middle and clown reaches of the Yangtze river. It is one of China's important ecological functional regions and is characterized by strong new tectonic movements, active geomorphological processes and a fragile ecology. The natural environment and human activity produce important effects on stability of slopes and soil-vegetation system, and the levels and types of soil erosion. The influence of natural factors, such as geology, landform, soil, vegetation, climate and hydrology，and the influence of human factors like population, land use and socio-economic conditions on regional water and soil erosion are studied through detailed field investigation. This research is of great importance to soil conservation，ccological construction and sustainable development.