Abstract: Based on water stage prediction-correction method, an 1D-3D coupled method is proposed to accurately simulate the surge wave caused by the transient process of hydropower stations in open channel, overcoming the inability of low-dimensional models to fully resolve the horizontal and vertical fluctuation of the surge wave, and low computational efficiency of high-dimensional models. Typical verification cases, including the tidal wave motion, the partial dam break flow and the open channel transient flow are simulated to analyze the accuracy of the proposed method. The simulated results are in good agreement with asymptotic theoretical solution and those yielded by commercial software. To futher demonstrate its capability in practical cases, the surge wave triggered by the transient process of the Gezhouba hydropower station is simulated. The maximum and minimum surge wave heights including its attenuation characteristics are analyzed. The results are in good agreement with those yielded by spectrum analysis, showing that the proposed method is capable of simulating practical transient flows in open channel.