Qingcaosha Reservoir, located in the Yangtze River Estuary, is currently the largest mid-river reservoir in China and serves as a crucial water supply source for Shanghai. The estuarine region where the project is situated is influenced by factors such as wind waves and tides, resulting in complex hydrodynamic conditions. To investigate the characteristics of pressure and flow field variations on the East Levee of Qingcaosha Reservoir under different wave and tidal conditions, this study established a three-dimensional numerical model of the reservoir's East Levee based on FLOW-3D, and physical model tests were conducted for validation. The numerical simulation results show good agreement with the experimental results. The research indicates that under incident wave action, a maximum offshore flow of 3.0 m/s can be generated in front of the levee. Furthermore, tidal level variations significantly influence the pressure and velocity at various points on the levee. The conclusions of this study can provide technical support for proposing reasonable beach nourishment and levee protection schemes for the Qingcaosha East Levee.