Accurately predicting the erosion regions is always a challenging point of numerical cavitation erosion simulation, which is beneficial for designing and extending the lifespan of the hydraulic machinery. The density-corrected SST k-ω turbulence model and the Sauer cavitation model were used to simulate the unsteady cavitation around NACA0009 3D twisted hydrofoil. The accuracy of the current numerical method was verified by comparing the cavitation shedding frequency and transient cavity behaviors in the experiment. Considering the energy transfer efficiency, a propagation relationship of cavitation energy from the flow field space radiation to the wall was constructed, thereby predicting the wall erosion load. By comparing the erosion energy and erosion load on the hydrofoil surface at different instants, it was found that compared with cavitation energy, the erosion load, which comprehensively considered the influence of erosion energy from the whole flow field on hydrofoil surface, predicted a wider coverage erosion area. Moreover, the average wall surface erosion intensity distribution was obtained. By time-averaging the wall surface erosion intensity solved from each instantaneous time step within 12 cycles, and by comparing the average wall surface erosion intensity obtained from the erosion energy and erosion load with the experimental erosion results, it was demonstrated that the erosion area predicted by time-averaged erosion load was more agreeable to the experiment result, indicating that it was necessary to consider the energy transfer efficiency when predicting cavitation erosion.