The first county along the Yellow river? Maduo County is the key region of the state natural protective source regions of Yangtse,Lancang and Yellow River.Supervising the Eco-environmental Change based on RS methods in the frangible and sensitive regions with high altitude will not only benefit the study of the natural law of frangible ecosystem in the cold and high altitude area,but also provide the operable and scientifically decision-making foundation for the local government.Based on two phases of the newest satellite image data ( the 1990 and 2000) and field investigation,the eco-environmental evolution processes since 1980s were analyzed.Analyses and discussions were made aimed at the understanding of the trend and causes of eco-environmental changes in the regions over the last 20 years.T he causes responsible for the eco-environmental changes in the regions were explored in accordance with the natural element including climate,frozen earth and hydrological change and human activity.