The emergency gate may produce large deformation and instability under the action of landslide-induced surge wave pressure. For the safe operation of the hydropower station, it is of great significance to study the dynamic response of the inlet emergency gate under the action of landslide-induced surge waves. In this paper, the landslide-induced surge waves in the reservoir area were simulated by a self-developed program, and the hydrodynamic pressure of the landslide surge is converted into the node load imposed on the finite element model of the flat steel gate. Then, the dynamic response characteristics of the gate under the action of landslide-induced surge waves were obtained by the dynamic time history method and evaluated according to the specification. The results show that under the hydrodynamic pressure of landslide-induced surge waves, the displacement and stress response values of the gate are the largest under the normal storage water level; whereas the dynamic response of the gate is more obvious under the dead water level. Under the normal water level, the maximum displacement response of the gate is 9.27 mm, and the maximum Mises stress is 192.06 MPa. The dynamic stress level of each component is quite low, which can all meet the requirements of the specification, so the gate can operate safely under the action of landslide-induced surge wave pressure.