Abstract: The super-high arch dams in China, such as Xiluodu and Jinping, have exhibited anomalous phenomenon of valley shrinkage during the initial impoundment. However, there is no observation on the deformation of the valley during excavation unloading. The deformation monitoring of the valley are analyzed during the construction period of Baihetan Hydropower Station, and provides relevant reference for the deformation monitoring of the same type of high arch dams. At the same time, it provides relevant basic guarantee for the monitoring and analysis of valley deformation in the initial stage of water storage.