Abstract: Hydrodynamic simulations were performed on a bionic water propulsion unit, and the mechanical properties of the propulsion unit were analyzed according to several simulation data under different conditions. This study was focused on the change laws of the lift, thrust and power curves of the propulsion unit at different speeds and altitude conditions, and several conclusions were summarized which would be helpful to design and optimize the bionic propulsion unit. Finally, relevant tests were done by means of an impeller mechanism test system, and the rationality of these conclusions was confirmed through test data. The results show that with increasing speed, the lift and thrust generated by the propulsion unit increase, the machinery efficiency and propulsion efficiency improve, but the lift efficiency decreases. The longer the distance between the axis of the propulsion unit and the water surface, within a certain range the greater the propulsion efficiency and lift efficiency are. Reasonable structure design can significantly improve the propulsion efficiency and lifts efficiency.