The increasing popularity of artificial heart pump therapy due to insufficient donor numbers and the growth of patients with advanced heart failure. The size of artificial heart pump leaf is one of the important parameters of artificial heart pump. The purpose of this study is to simulate and analyze the flow field of artificial heart blood pump by using dynamic grid technology in CFD and on the basis of existing medical data, and improve the flow state of blood in the blood pump by improving the impeller inlet structure, so as to enhance its anti-hemolysis performance. For this purpose, key parameters (such as tip clearance) of artificial heart pump blades were optimized based on CFD flow field simulation. The result showed that decreasing the tip clearance from 100 μm to 60 μm, would cause a stability in the pump efficiency. The study shows that CFD in the blade size of artificial heart pump is beneficial to the optimal design of blood pump chamber.