Abstract: Combining the actual construction situation of Longbeiwan hydropower station concrete face rockfill dam project, the three-dimensional finite element analysis method is used to simulate the deformation development process of extruded sidewall during the construction process of concrete face rockfill dam. The dam deformation rules and development rules of extruded sidewall due to dam deformation are investigated. According to the monitoring data, deformations of the dam body and extruded sidewall are analyzed. By comparing the calculated results of three-dimensional simulation with the measured data. The reasonableness of three-dimensional simulation analysis for the dam is verified. The filling program for the dam is adjusted according to the calculated results. The deformation of extruded sidewall during construction is significantly reduced after the filling order for the dam is adjusted.