Ecological spur dike is a new type of regulation member based on hydraulics and ecology. It not only controls river water level and maintains slope stability, but also promotes ecological restoration. In this paper, Flow-3D fluid mechanics software is used to analyze the flow velocity, turbulent kinetic energy and other key hydrodynamic factors of the new semi-circular member. The results show that the fitting result of flow velocity based on Flow-3D numerical simulation is good, and it is feasible to use this software to study the hydrodynamic characteristics of complex components in waterway regulation engineering. The diaphragm in the new semi-circular member divides the cavity into two areas, the flow velocity and turbulent energy in the upper layer are obviously higher than those in the lower layer, and the flow velocity and turbulent kinetic energy in the lower layer are basically not affected by the external flow velocity. The upper and lower layers of the member have different ecological effects and their hydrodynamic characteristics are suitable for the survival of fish and benthic organisms respectively.