Abstract: Two accumulation bodies(B2,B20) on the left bank of Jinsha River,back of the dam of one hydropower station in Yunnan Province.They have enormous size and close to the dam,and have a good reliability in the natural state based on massive working of survey and test.Analysis shows that part of the accumulation bodies is likely to be destructed in the conditions of rainstorm earthquake.Engineering construction and atomization by flood discharge with further influence the safety of temporarily roads and permanent buildings.We understand the deformation mode through the stability analysis,and adopt the pertinence engineering treatment measures to meet the standard requirement and ensuring safety of engineering construction and operation.