Abstract: Polyaniline (PANI) modified graphene oxide (GO) was used to prepare polyaniline (PANI) reinforced epoxy resin (EP) composite coatings containing different amounts of graphene oxide on the surface of Q235 low carbon steel through chemical oxidative polymerization. The influence of graphene oxide content on the adhesion and corrosion resistance of the composite coating was studied through adhesion testing, electrochemical testing, and immersion testing. The results show that the corrosion resistance of the coating increased with the increase of graphene oxide content, and the composite coating had the best corrosion resistance effect when the graphene oxide mass fraction was 0.4%. The addition of graphene oxide enhanced the corrosion resistance of the composite coating compared to PANI/EP coating. The adhesion of PANI/GO/EP composite coating was level 0, the anti-corrosion efficiency reached 99.86%, and the long-term effective protection time was 91 days. Compared with PANI/EP coating, the long-term effectiveness of PANI/GO/EP composite coating was improved by about 42 days.