The invention discloses a waterborne epoxy anticorrosive coating and a preparation method thereof. The aqueous epoxy anticorrosive coating contains a component A and a component B according to a massratio of the component A to the component B of (3 to 5): 1. The component A comprises, by mass, 35-40 parts of a waterborne epoxy emulsion, 1-2 parts of carbon black, 10-15 parts of mica powder, 10-15parts of precipitated barium sulfate, 5-10 parts of graphene oxide / alkylbenzene sulfonate, 1-2 parts of a wetting dispersant, 0.3-0.5 parts of an antifoaming agent, 0.3-0.5 parts of a leveling agent,1-2 parts of a thixotropic agent and 20-30 parts of deionized water. The component B comprises, by mass, 7-10 parts of an aqueous epoxy curing agent, 3-5 parts of a cosolvent, 10-15 parts of deionized water and 1-3 parts of an amino group-containing silicone monomer. The waterborne epoxy anticorrosive coating has excellent anti-corrosion performance, good adhesion and resistance to cathodic disbonding, and is suitable for application in a marine environment.