To analyze the internal flow of the engine cooling water pump (ECWP) under thermodynamic effect, Zwart cavitation model based on the Rayleigh-Plesset equation is corrected, and NACA0015 hydrofoil was selected to verify the corrected model. The cavitation performances of ECWP with different temperatures were numerically simulated based on a corrected cavitation model. Research results show that simulation values of pressure distribution coefficient in hydrofoil surface at 70 °C are in closest agreement with experimental values when the evaporation and condensation coefficients are 10 and 0.002, respectively. With the decrease of absolute pressure in pump inlet, bubbles firstly occurred at the blade inlet side near the suction surface and then gradually extended to the pressure surface, finally clogged the impeller passage. Compared to the inlet section, the cavitation degree is much more serious close to the trailing edge. With the temperature increases, the cavitation in ECWP occurs in advance and rapidly, and the temperature plays an important role in promoting cavitation process in ECWP. Based on the unsteady simulation of ECWP, the influence of cavitation on the performance characteristics is studied. The results provide a theoretical reference for the prediction and optimization of the cavitation performance in ECWP.