With the operation of the Three Gorges reservoir,many of the old landslides were newly deformed.The Woshaxi landslide was one of the typical landslides in the Three Gorges Reservoir area,which had been continuously deformed since 2003 and the deformation showed a certain periodicity and regularity.According to the geological survey and professional monitoring data,the landslide deformation characteristics were analyzed,and the influence factors and deformation mechanism were obtained.The results show that the sandstone mudstone and topography provided conditions for landslide deformation.The main factor affecting the deformation was the reservoir water level fluctuation which had saturated loading effect and hydrodynamic pressure effect when the water level dropped down.A huge seepage pressure was formed to the outside of the slope,which resulted that the stability of the slope decreased and the deformation produced.The secondary sliding body is in an unstable state and if the rate of water level increases it will be in an unstable state.Studies provide a basis for the landslide monitoring,early warning and prevention,as well as the reservoir operation.