In order to solve the long-term corrosion problem for large-scale steel box girder bridges, this paper relies on Zhejiang Zhoushan Xihoumen Bridge, combining with arc spraying anti-corrosive coating technology and nano-modified sealing coating, the arc spraying nano sealing composite coating system was designed, comparing the conventional arc spraying composite coating system and innovative design solutions of arc spraying nano sealing composite coating system. Different arc spraying metal coating materials were recommended for different corrosive environments. The technical parameter comparison of nano sealer and common anti-corrosion epoxy primer were analyzed comparatively. Quality requirements and testing methods of arc spraying nano sealing composite coating system coating procedure arc briefly introduced.