Accurate prediction of the water inflow for the tunnels is of great significance to ensure the underground construction safety of pumped storage power station. Based on the hydro-geological conditions of the pumped storage power station and the layout of the underground tunnels, three methods including the water balance method, the long narrow horizontal tunnel method and the numerical method were used to predict the water inflow of underground tunnels in the power station area, and the simulated results were compared with the measured values. The results showed that the predicted normal water inflow values of water balance method, long narrow horizontal tunnel method and numerical method were 4409.58, 4976.78 and 4242.24 m3/d, respectively, and the largest inflows were 5167.56, 5463.31 and 4763.43 m3/d, respectively. Furthermore, the predicted water inflow using the numerical method agreed well with the measured value, which was an important reference. During the process of next construction stage, water inflow predicted from the numerical method can be a very good guidance for the management departments in design of drainage tunnel.