Abstract: The tidal bore in Qiantang River leads to sharp rise of water level and powerful impact on the riverbed, which will cause the tunnel vibration. However, it is not able to predict the vibration of tunnels under tidal bore clearly now. Consequently, it’s necessary to conduct feasible researches on the dynamic response of the tunnels, especially the characteristics of the longitudinal dynamic response. Model tests on dynamic responses of a small tunnel instrumented with miniature accelerometers are performed. Vibratory loadings are produced on the soil surface by an electric exciter to simulate dynamic loading from tidal bore. The test results are compared with those from a simplified method to investigate the dynamic responses of the tunnel. The factors that affect the dynamic response of the tunnel are explored.