Objective To improve the blood flow regime and hemolysis performance for two-direction hydrodynamic suspension blood pump of artificial heart，the structure of the impeller inlet was changed，and we used computational fluid dynamics method to simulate and analyze the flow field of blood pump. Methods Considering hemolysis performance of the blood pump，we used FLUENT6.3 software to analyze the flow field of centrifugal blood pump based on N-S equations and k-ε standard double-equations turbulent model. Then，the influence analysis of the flow field velocity with the impeller inlet structure change was proceeded as the impeller rotating speed in design condition，the relationship between maximum velocity and hemolysis level was also analyzed，and the pump structure was optimized. Results By optimization，the disorder phenomenon of blood pump flow field was improved. The shear stress and exposure time which influenced the hemolysis were decreased，hemolysis performance was improved. Furthermore，the maximum flow velocity had the potential to show flow field as a visual indicator under design condition in the process of optimization. Conclusions Numerical analysis of this research accumulated certain experience to design centrifugal blood pump with two-direction hydrodynamic suspension.