Abstract: In order to reduce the flow-resistance coefficient of mixed-flow pump in a marine ship water circulating system, and improve the automatic flow characteristics as well as enhancing its artesian circulation function, simulation optimization and experimental study of low flow-resistance hydraulic components were carried out based on CFD simulation. Firstly, a preliminary design scheme was determined through the simulation analysis, which led to the achievement of the design requirements for its hydraulic performance. Then, in order to further reduce the hydraulic loss and the flow-resistance coefficient, the main influencing factors of flow resistance were determined by stochastic finite element analysis method, and the main components such as impeller, guide vane, volute and outlet pipe were optimized and improved. Finally, based on the optimization scheme, manufacturing of the prototype and validation tests were performed. The result shows that the total wrap angle of the blades and guide vane angle are the main influencing factors for the flow-resistance of hydraulic components of the mixed-flow pump. The simulation prediction results are consistent with the test results of the prototype. The optimized pump has smooth internal flow, reasonable pressure distribution and velocity distribution. There is no obvious shedding and vortex, the overall flow-resistance coefficient drops significantly, and the hydraulic performance meets the design requirements. Therefore, the proposed simulation optimization method for low flow-resistance hydraulic components is proven to be feasible.