The invention discloses a centrifugal heart pump impeller of a closed structure. The centrifugal heart pump impeller is characterized in that blades are in unconventional design and are in centrosymmetric distribution to form 4-6 round flow channels which are identical in internal section, and setting angles at an inlet and an outlet of every blade are 20-30 degrees and 25-40 degrees respectively.The centrifugal heart pump impeller has the advantages that when the impeller acts on blood, red blood cells in the round flow channels cannot be destroyed, so that the breakage rate of the red bloodcells is decreased effectively; the round flow channels made of engineering materials are quite smooth in surface, and accordingly friction loss between the impeller and the blood is reduced greatly,no obvious effect on blood temperature change is caused, the heart pump efficiency is improved, energy for driving is reduced, and safety and reliability of a centrifugal heart pump are enhanced; thecentrifugal heart pump impeller can be applied to the heart pump.