Graphene（G）material modified waterborne heavy anticorrosive coatings is oneof the hot research areas in the field of coatings. At present，there are few researches on the synergistic effect of graphene and traditional barrier fillers，and the synergistic mechanism is not clear. In this paper，the effects of graphene/micaceous iron oxide（MIO）on the shielding properties of the coating were studied by water absorption and electrochemical impedancespectroscopy. The interaction mechanism between graphene and micaceous iron oxide fillers inthe coating was discussed by means of scanning electron microscopy（SEM）and X-ray energyspectrometry（EDS）. The results showed that：When 0. 35% graphene was added to the waterborne epoxy MIO coating，the water absorption of the coating increased by 2. 06%compared with that of the waterborne epoxy MIO coating. The electrochemical impedancespectroscopy test results showed that the arc radius of the waterborne epoxy G/MIO coating athigh frequency decreased compared with that of the waterborne epoxy MIO coating，and the impedance mode value of the coating at low frequency decreased. The coating capacitanceincreased by 5. 018×10^-5 F/cm²，and the coating resistance decreased by 0. 86×10⁴ Ω ·cm²， indicating that the shielding effect of the coating became worse when graphene was added tothe waterborne epoxy MIO coating. Through the characterization of the coating cross-section，it was found that when graphene and micaceous iron oxide exist in the waterborne epoxy coatingat the same time，the shielding performance of the final coating was determined by thesuperimposed effect of the distribution and dispersion of the two pigments in the coating.