The invention relates to coating technology, in particular to a polyaniline modified glass flake heavy-duty anti-corrosive coating and a preparation method thereof to solve the problems that when the prior glass flake anti-corrosive coatings are constructed, most of the glass flake anti-corrosive coatings require to coat primer on the surface of steel or other metal matrix to improve the corrosion resistance and prevent corrosion between the coat and the interface of the matrix, and the like. The polyaniline modified glass flake heavy-duty anti-corrosive coating comprises epoxy resin, a polyaniline modified glass flake, an amine curing agent and the like. A polyaniline coating layer is formed on the surface of the glass flake by an oxidative polymerization method; the glass flake after the treatment has the passivating effect on metal; and a phytic coating layer on the surface of the glass flake also has the corrosion inhibiting effect on the metal. The polyaniline modified glass flake heavy-duty anti-corrosive coating has strong corrosion resistance and permeability resistance, can be applied to heavy-duty anti-corrosive projects such as petrochemical equipment, pipelines, offshore oil platforms, wharf facilities, shipping and the like, and is particularly suitable for protecting wave splashing zones and tidal difference zones.