Abstract: It is to predict the settlement of soft soil foundation under reservoir dam and to study the law of settlement of soft soil foundation and the law of dissipation of pore water pressure. A plane-strain FEM model was established to analyze the settlement of soft soil foundation for reservoir dam. The results showed that the settlement of soft soil foundation included initial stages, quick stages and slow stages. The laws governing the settlement and the dissipation of pore water pressure could be described with the Hill model and the Expdec2 model, respectively. The maximum of settlement and the additional settlement due to dam mass and the maximum of horizontal displacement were obtained. The results can offer an important reference to the construction of dam and the subsidence of similar soft soil foundation.