Abstract: The topography,sliding surface and ground water level of landslides in reservoir areas would appear with complex geometries and typical 3D features.To evaluate their stabilities more rationally,the analysis could be adopted by use of 2D residual thrust method and 3D limit equilibrium method under the same condition.For a practical example from a reservoir area,some aspects were processed by 2D and 3D methods respectively,such as the inversion of two strength parameters,the calculation of stability factors in various typical water levels of the reservoir,and the sensitivity analysis of stability factors under the condition of rising and drawdown of water levels.It was indicated that 3D method was more rational and more objective than 2D method.And,through the integrated analysis of the 2D and 3D results,the better conclusion of the slope stability could be gained.Therefore a better way to evaluate the stability of landslides in reservoir areas would be proposed.