[en] The synergistic erosion-corrosion and corrosion characteristics of mild steel were studied by using rotating disk apparatus and immersing in 0.05 wt.% SiC suspension, respectively. The difference between cavitation erosion and corrosion was determined by scanning electron microscope (SEM), positron annihilation lifetime spectra (PALS) and X-ray photoelectron spectroscopy (XPS). It was found that the propagation of cracks in pit area induced by cavitation erosion did not appear in the course of corrosion. The PALS results showed that the size and number of vacancy cluster induced by cavitation erosion was much larger than that induced by corrosion damage. The results of core level band spectra indicated that there were chemical shifts in the case of cavitation erosion and no chemical shifts except 40 min corrosion in immersion process. The results of valence band spectra implied that the oxidation of mild steel induced by cavitation erosion was more than that induced by corrosion damage