Based on the three-dimensional design platform, this article conducted parametrization of blade leading and trailing edge positions, and analyzed the influence of different position parameters on mixed-flow pump hydraulic performance and internal flow with model test and numerical simulation. The results showed that the hydraulic efficiency of a mixed-flow pump increased slightly when the position parameter _h of the blade leading edge on the hub increased, and increased significantly when the position parameter _t of the blade leading and trailing edge positions on the shroud increased. However, with _t increasing, the growth rate of decreased. Numerical simulation has shown that by selecting a proper value of _t, the impeller energy conversion capacity can be effectively improved, and the distributions of static pressure and total energy can be more uniform in the flow passage. Meanwhile, with _t increasing, blade angle on the blade trailing edge decreased. Correspondingly, the absolute velocity in the outlet zone decreased, and the hydraulic loss in the outlet zone also decreased, which is beneficial to improving hydraulic efficiency of the mixed-flow pump. Within the value range of 7–9°, with different combinations of position parameter _t1 of the blade leading edge on the shroud and position parameter _t2 of the blade trailing edge on the shroud, the mixed-flow pump hydraulic efficiency and blade wrap angle show a linear positive correlation, suggesting that an increase in could significantly improve impeller energy conversion capacity. Compared to _t1, _t2 has a more significant influence on and . Thus, the value of _t2 should be carefully attended to during design process.