According to the specific geological and topographical conditions at slope of the Hydropower Station, considering the shape and size of simulation geometric model, the position relationship between the simulated area and buildings of terminal area and boundary conditions, the dynamic model which is fit to the geological structure are selected. Using the measured stress distribution as constrained conditions, 3D initial geostress field of research area are simulated using FLAC3D program. The result of simulation analysis shows that 3D initial geostress field of research area are accurately simulated based on good combination between the measured stress data and numeriacal simulation. So as to provide a reasonable basis for further condition simulation, such as excavation and unloading conditions. It has important significance for similar geological environment projects that the method is successfully applied to simulate initial geostress of this area.