It is considered that excavation and fault are the most important factors causing the displacement of surrounding rock of underground powerhouse.Based on this viewpoint,this paper puts forward a deterministic factors influence model for the displacement forecast of surrounding rock of underground powerhouse.The fault factor influence model and excavation footage factor influence model are respectively studied,including their modeling method and processes.Afterwards,a two factors influence model for the surrounding rock displacement of underground powerhouse is gotten,It is proved in practical engineering that this new model is of high forecast precision,and can be used to practical engineering.