The work aims to evaluate the properties of the self-developed polyurethane supporting system. The evaluation methods of steel structure coating properties in marine atmosphere were summarized. The matching of acrylic polyurethane coating with zinc-rich primer and epoxy primer was investigated through the NORSOK M-501 cyclic corrosion test, and the aging resistance of the self-developed acrylic polyurethane coating was compared with that of foreign similar products through QUV accelerated aging experiment. Corrosion spreading resistance of the supporting system consisting of polyurethane coating and zinc-rich primer was better than that of the supporting system consisting of polyurethane coating and epoxy primer. For the self-developed polyurethane coating system subject to 4200 h of cyclic aging, corrosion in the marked position spread by 5.56 mm (less than 8 mm specified by NORSOK M-501 standard), adhesive force decreased from 12.26 MPa to 9.83 MPa at the attenuation amplitude of 19.8% (less than 50% specified by NORSOK M-501 standard). After aging for 3000 h under UV-irradiation, 60° glossiness of the self-developed polyurethane coating decreased from 81.5 to 66.5 while the gloss retention rate was 82.94%. The self-developed polyurethane coating system is of excellent marine atmospheric environmental resistance. Its cylic aging resistance and UV-light accelerated aging resistance are equivalent to that of foreign similar products.