The work aims to enhance the corrosion resistance of fluorocarbon coating by studying its failure process in 3.5% NaCl solution. Functionalized graphene obtained by using silane coupling agent for graft modification was added to fluorocarbon resin to fabricate a series of fluorocarbon coatings reinforced with various content of graphene. Structural properties and dispersibility of graphene in the coatings before and after being modified were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Moreover, the electrochemical corrosion behavior and failure process of the coatings in simulated seawater (3.5% NaCl solution) were investigated by virtue of AC impedance spectroscopy and potentiodynamic polarization curve. In addition, salt fog resistance of the coatings was studied as well. The results showed that the graphene surface could be grafted to functional groups successfully and was well dispersed in the coating. The graphene could be well protected from aggressive mediums. Anti-corrosion performance of the coatings first increased and then decreased as the graphene content increased. Provided with graphene coating of 0.4% (mass fraction), corrosion current density of the coatings 2.209×10–10 A/cm2 and that of fluorocarbon coating 6.026×10–6 A/cm2, significant reduction of corrosion current density contributed to optimal corrosion resistance. Finally, during the 360 h of immersion which fell into early immersion stage, the FEVE-0.4%G coating showed an effective corrosion resistance and could protect Q235 steel substrate in the best manner. The corrosion resistance of fluorocarbon coating can be improved greatly by graphene.