Abstract: In order to conduct a preliminary exploration of the interaction characteristics of the tidal bore acting on the ancient seawall, the tidal bore pressure on the ancient seawall is observed on the north bank of Haining reach of the Qiantang River. The upper structure of the ancient seawall was built with big strip stones. The time and space distribution characteristics of the tidal bore forces on these stones are analyzed in this paper， considering the effects of the bore height and the incidence directions. The combined action of the typhoon with tide bore is preliminarily analyzed by use of dynamic measurements. This analysis results can provide a reliable reference basis for the protection and design of the ancient seawall in the Qiangtang River.