Abstract: The two-phase flow model is used to simulate the cavitation of the double-suction centrifugal pump under different flow conditions, and the development process and performance evolution of the double-suction centrifugal pump are studied. The results show that with the development of cavitation, the head and efficiency of the double-suction centrifugal pump decrease significantly, and the cavitation in the impeller first occurs near the hub of the suction surface of the blade, and spreads to the plate and the outlet of the blade. In the judgment of critical cavitation, the efficiency reduction of 1% is more reasonable than 3% of the head decrease, but neither is suitable as the judgment basis for cavitation inception. Based on the development law of cavitation in the impeller, the efficiency reduction of 0.1% may be used as the judgment basis for cavitation inception of double-suction centrifugal pumps.