Different mass ratios of graphene nanoplates (G
nps) were added into Zn/epoxy (EP) coatings with 40%Zn content to prepare G
nps-40%Zn/EP composite coatings. The Zn/EP coating with 70%Zn content was also prepared as the contrast. The Raman spectra, SEM, salt spray test and electrochemical technique et al were applied to evaluate the barrier property and cathodic protection effect of G
nps-40%Zn/EP composite coatings. The anticorrosive effects of G
nps-40%Zn/EP composite coatings and 70%Zn/EP coating were compared to explore the possibility of reducing Zn content by adding G
nps into Zn/EP coating. To further clarify anticorrosive mechanism of Zn/EP coating with varying G
nps addition, the anticorrosive model was established. The results indicate that G
nps could be well-dispersed into Zn/EP coatings, but disorder parameter of G
nps increases with the increasing of G
nps addition. While G
nps addition are 0.3%, 0.5% and 1.0%, the physical shielding performance of Zn/EP coating can be significantly improved; while G
nps addition are 0.5% and 1.0%, the cathodic protection effect of Zn/EP coatings can be significantly enhanced; While G
nps addition is 1.5%, both shielding performance and cathodic protection effect of Zn/EP coatings are not obviously improved. For G
nps-40%Zn/EP composite coating, the best addition range of G
nps is 0.5%-1.0%. The suitable addition of G
nps can reduce Zn content in Zn/EP coating and lower the production cost.