Abstract: The electrochemical behavior of 42CrMo bearing steel in 3.5%NaCl solution was studied by means of open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization tests, and the influence of temperature and corrosion time on the electrochemical process were studied. The results show that the electrochemical process of 42CrMo bearing steel in 3.5%NaCl solution was mainly activated dissolution. With the increase of temperature and immersion time, the electrochemical activity of 42CrMo steel increased significantly, behaving a decreasing R_ct value and an increasing J_corr value. This change indicated the significant decrease in corrosion resistance. Macromorphology analysis showed that the surface of 42CrMo bearing steel in 3.5%NaCl solution was mainly localized corrosion, accompanied by corrosion pit characteristics.