Abstract：The high slope on both banks in the region of lock site of a hydropower station in southwest China，has the surface with severe weathering and relief，and has predominant flexure-tension fracture distortion. So the disaster，such as falling，desquamation，happens from time to time. Thus it appears especially important to accurately evaluate the characteristics，stability and hazard degree of the slope. Based on the site survey of engineering geological environmental condition and comprehensive analysis，firstly，the characteristics of the high slope on both banks are detailedly studied，such as structure types，combination between structural plane and slope surfaces，weathering of rock mass and the physical and mechanical property. Then the quantitative grades are given to the quality of rock mass. Accordingly the stability and the potential engineering effects are synthetically evaluated combined with actual slope. Finally，It is concluded that the stability of the slope on both banks is poor，especially on right bank. This situation will have a strong influence on lock site and water intake under the slope.
