Abstract: Reservoir bank caving is complex geological environment problem,and it is a process of the slope substance changed from stability to destruction during the variation of the reservoir water level.Reservoir bank caving played a very important controlling role in the safety and the long operation,especially the regular operation of the highway and railway and the resettlements around the reservoir basin.Some loose deposits in reservoir area had induced 16 deformation of different scale because of the water filling of the principal reservoir of the Southwesten China in 2006,and they affected the residents safety on slope and normal running of the highway around lake seriously.Based on the on-site geological survey and exploration and experimental results,particularly the identification of the different bank collapse borders under different reservoir water levels,a bank collapse prediction of the loose accumulation slope with different shaping factors and granulometric composition was analyzed according to the method of the circular sliding surface search systematically,and finally the width of bank collapse under the control of different soil types,slope gradient and reservoir water levels was given.On the basis of the above studying results,a comprehensive correlation analysis was made,for example,the width of bank collapse and the soil type(especially the cohesion and internal frictional angle),slope gradient,the height difference between the exit points on the slope face and the water level,and hydrodynamic pressure of groundwater,and the predictive equation was educed,concerning the width(B) of the loose deposits’s bank collapse marked by coarse-grained soil under different control factors.