Abstract: 2Cr13 type high nitrogen corrosion resistant plastic die steel was added with 0.5wt% Mo. The effect of Mo element on microstructure, mechanical properties and corrosion resistance of the steel after quenching and tempering was studied. The results show that the addition of Mo reduced the austenite phase zone of the test steel, and after quenching the residual austenite volume fraction was 8.49%, which was lower than that in the Mo-free test steel (9.05%). The addition of Mo improved the strength, hardness and impact absorption energy of the test steel, and the yield strength increased by 12%. After the salt spray corrosion test, pitting of the tempered test steels mainly occurred, and the pits on the surface of the Mo-containing test steel were less in number and size, and the corrosion rate was 0.072 1 g·m^-2·h^-1, which was much lower than that of the Mo-free test steel (0.161 2 g·m^-2·h^-1). There was a clear passivation zone in the polarization curve of the Mo-containing test steel, but there was no passivation zone in the Mo-free test steel. The corrosion resistance of the Mo-containing test steel was better than that of the Mo-free test steel.