Based on the limit equilibrium theory,combining with the horizontal slice method,we convert the vertical inter-slice force relationship of Bishop method to the horizontal soil strip,derive the theoretical calculation formula of the stability safety factor of homogeneous bank slope under the action of water flow traction force,and compare the results with the simulation results of ABAQUS finite element software’s strength reduction method.Then we analyze the influence law of water flow traction force on the banks with different slope ratios combining with engineering practice.The results show that the calculation results of theoretical calculation formula and simulated by software are basically consistent,and the error does not exceed 2.1%.The water flow traction force of river will increase the sliding moment and reduce the stability safety factor of the river bank slope soil.When the soil is in a critical stable state under the action of multiple factors,such as rain and soil degradation at toe etc,the water flow traction force can become the key factor for landslide initiation.When the river bank slope is sliding instability,the water flow traction force will cause the sliding body to slide further towards the channel,which can increase the harm of landslide to the safety of the channel.The steeper the slope is,the greater the influence of the flow traction force on the slope stability safety factor is.In the analysis of bank slope stability of high and steep rivers,the water flow traction force is an external load that cannot be ignored,which is as important as heavy rainfall,debris flow and other factors.