Abstract: Microstructures and electrochemical corrosion behaviors in simulated seawater (3.5wt%NaCl solution) at 20, 50℃ of domestic D36, F460 and F690 steels for marine engineering were studied. The results show that the microstructure of D36 steel rolled by thermo-mechanical control process consisted of ferrite, pearlite and a little widmanstatten structure. The microstructures of F460 and F690 steels after quenching and tempering treatment were both composed of fine bainite lath. In the NaCl solution, the corrosion resistance and pitting corrosion resistance of D36, F460 and F690 steels increased in turn. Compared with those at 20℃, the free corrosion current density at 50℃ of the three tested steels increased significantly, and the corrosion resistance decreased. After long-term immersion in the NaCl solution, the thicknesses of surface corrosion product film on D36, F460 and F690 steel decreased in turn, and the element type in the corrosion product film increased in turn. The three tested steels showed overall uniform corrosion characteristics.