The invention discloses a preparation method of a barium sulfate-calcium carbonate compound modified epoxy resin coating. The preparation method is characterized in that the compound modified epoxy resin coating is prepared by heating a graphene oxide dispersion liquid, adding p-phenylenediamine dropwise, stirring, dissolving, reacting at the constant temperature, filtering, centrifuging and washing with deionized water and absolute ethyl alcohol, drying to obtain a graphene oxide-p-phenylenediamine composite; stirring a barium sulfate suspension liquid in a thermostatic bath, adding a compound modifier, stirring, filtering while the mixture is hot, drying, grinding, and screening to obtain modified barium sulfate; drying calcium carbonate in a vacuum drying oven, adding a silane couplingagent and a titanate coupling agent, heating and modifying calcium carbonate through a dry method; mixing and stirring deionized water ultrasonic dispersion liquid of the graphene oxide-p-phenylenediamine composite and deionized water ultrasonic dispersion liquid of a waterborne epoxy resin, ultrasonically treating, layering, pouring out water, heating the mixed solution in the drying oven, mixingwith a waterborne epoxy hardener, ultrasonically stirring, adding an emulsifier, a dispersing agent, a defoamer and a wetting agent, and ultrasonically treating.