The thickness, width, and outlet deflection angle of the cyclone pump vane are selected as research objects to enhance overall cyclone pump performance and minimize its energy loss. Numerical simulations of the flow field are conducted for five groups of impellers with different structures based on the realizable k–ε turbulence model. The analysis incorporates the velocity and pressure field distributions under various operating conditions to demonstrate how the primary geometrical parameters of the vane affect the cyclone pump’s performance. The results show that although increasing the thickness of the vane can boost the pump’s maximum efficiency within a limited range, excessive thickness narrows the flow channels between the vanes. This results in the pump reaching its lowest efficiency at a thickness of 4.4 mm. To prevent efficiency loss, the blade width should remain within a certain range. A slight increase in blade width improves the cyclone pump’s flow stability, and its effect on the head is less than its impact on efficiency. Additionally, as the deflection angle at the vane’s outlet increases, the low-pressure zone at the impeller’s inlet slightly expands, and the pressure in the volute outlet flow passage slightly increases. These changes enhance flow stability and result in a more consistent pressure distribution in the volute pump’s flow passage.