Most papers focused on the hydraulic conditions and seldom took the factor of ships into consideration when they studied the impacts of navigation-turbulence around bridge pier upon clear width. This paper establishes a two-dimensional hydrodynamic model by using dynamic meshes of the software Fluent. How the ship affects the turbulence pattern of pier is analyzed, and the relationship of span wise distance between ship and pier as well as the change of force on ship over time is studied when the ship passing through the bridge. The results show that both the lateral flow in front of pier and the turbulent flow behind it could result in a force upon ship. The magnitude of the force is related to the distance between ship and bridge. The motion of ship can increase the weaving amplitude of pier wake and the width of turbulent area after it passes through the bridge.