Abstract: Conventional observation methods for surface deformation of reservoir dams cannot realize automatic observation, and their accuracy is easily affected by visibility and climatic conditions, and the acquisition frequency is low, so they can only monitor static deformation. Through the comparison and analysis of the optical method and the BeiDou Satellite Navigation System (BDS) surface deformation monitoring technology, combined with a reservoir dam project, the feasibility study of the BDS monitoring of the static and dynamic deformation of the reservoir dam surface is carried out in this study. Engineering practice shows that the BDS can not only monitor the static deformation of the dam surface at the millimeter level, but also can observe the dynamic deformation of the dam surface with an acquisition frequency of 1 Hz under the action of earthquakes so as to meet the specification requirements. This provides an effective technical solution for the unified monitoring of static and dynamic deformation of dams in active seismic areas, and is of great significance to post-earthquake dam safety assessment or emergency treatment.