Objective To investigate the impact of variations in volute cross-sectional area on the flow characteristics and hemolytic performance of centrifugal blood pumps by designing six volute structures. Methods Computational fluid dynamics and the Lagrangian method were used to analyze flow characteristics and predict hemolysis in blood pumps with different volute designs. Results The annular volute pump showed the poorest hydraulic performance, while the hydraulic performance of the S-shaped volute was the best improving by 35.29% compared to that of the annular volute. Some volutes experienced stagnation zones at the helical inlet (0°–90°) and significant backflow at the outlet (270°–360°). The downward concave-shaped volute had the highest hemolysis index (HI), i.e., 9.59 × 10-4. Meanwhile, the HI of the annular volute was the lowest, which was 71.85% less than the concave-shaped volute. Conclusions Reducing the gradient of the area variation at the helical inlet and outlet can prevent flow stagnation and backflow. A higher HI arises due to the prolonged exposure of red blood cells to high shear stress. This study provides a theoretical basis for designing and optimizing volute structures of centrifugal blood pumps.