The stability of silty bank slope under rainfall is one of the most important problems faced by engineers.Against the silty bank slope of the upper approach channel of some ship lock in North Jiangsu,the numerical model for the stability analysis of unsaturated silty bank slope is established,which considers the coupling effect of rainfall infiltration and slope plastic deformation.The effects of saturation,saturation line,matrix suction,safety factor and slope ratio on the stability of unsaturated soil bank slope under different rainfall intensity are discussed.It shows that the most dangerous slip surface of the unsaturated silty bank slope caused by rainfall increases quickly,and the rainfall intensity of 50 mm/d will cause the most dangerous slip surface to move up about 2.4 m.The head of the slope immersion line is raised by about 50 cm with every 10 mm/d increase of rainfall.It also shows that the safety factor of the bank slope decreases linearly with the rainfall intensity,and the decrease of safety factor during the rainfall process increases with the increase of the breaking ratio.