The work aims to improve corrosion resistance of metal materials in marine environment. Ni-Zn-P alloy coating and Ni-P/Ni-Zn-P bilayered composite coating were prepared on Q235 steel by virtue of chemical plating. Surface morphology and fracture surface of the coatings were analyzed with SEM and EDS. The Ni-P/Ni-Zn-P bilayered composite coating was more uniform and smooth than Ni-Zn-P alloy coating, and the cell boundary was more continuous and dense as well. Cross section thickness of Ni-Zn-P alloy coating was about 6.5 μm, and Zn and P mass fraction nearly 4% and 14% respectively. Overall thickness of Ni-P/Ni-Zn-P bilayered composite coating was about 7.5μm, thickness of inner coating about 2.3 μm, P mass fraction about 9%; the outer coating about 5.2 μm, Zn and P mass fraction of about 5% and 11% respectively. After being corroded for 144h in 5% solution, the Ni-Zn-P alloy coating was severely damaged and many cracks were present. The Ni-P/Ni-Zn-P bilayered composite coating remained intact and was subject to localized corrosion instead of serious damage, indicating that the bilayered coating was more resistant to corrosion. Corrosion rate of Ni-P Ni-Zn-P bilayered coating was significantly lower than that of Ni-Zn-P alloy coating, corrosion resistance of the former was better as well.