In recent years the environmental problems become more and more urgent. Great emphasis has been put on water power development in our country, as a renewable energy source. But it is not an absolutely clean power source. Both in construction period and in operation time water power projects will? bring negative influences on the environment and ecological condition. Rock and earth excavation of huge quantity in construction works destroys the vegetation cover and soil on the work site entirely, so causes water and soil erosion in large area. Potential landslide areas increase. It is necessary to make a comprehensive research and analysis including the synthetic impacts on environment and ecological condition over a long period? when the water power developments in south west area of our country are to be planned and implemented. Several suggestions to decrease the rock and earth excavation are given.