[Purposes] This study investigated the hydrodynamic processes in the Pearl River Estuary under the influence of Typhoon "Hato". [Methods] The hydrodynamic processes in the Pearl River Estuary and the nearby sea area were simulated using the FVCOM model based on an unstructured grid. [Findings] Among the eight outlets of the Pearl River Estuary, Modaomen was the one that most severely affected by the typhoon, with a maximum water increase of 0.79 m, followed by the central outlets （0.30-0.65 m), and the Wailingdingyang outlet （0.20 m). Under the influence of the typhoon, the maximum increase of surface current speed was 0.50 m/s. The maximum surface current speed of the storm surge was twice that of the astronomical tide at the same time. The wind direction varied within the range of 0-180° along with the movement of the center of the typhoon. [Conclusions] The current velocity responded earlier to the typhoon than the tide level and was more severely affected by the typhoon. The typhoon exerted a stronger influence on the surface current speed than on the vertical mean current speed. The storm surge in the northeast direction of the track of Typhoon "Hato" induced larger water increase than that in the southwest direction, and the area located in the northeast of the typhoon suffered more serious storm surge disaster.