The invention discloses waterborne bicomponent epoxy iron red shop primer and a preparation method thereof, and relates to a coating composition. The waterborne bicomponent epoxy iron red shop primerprovided by the invention comprises a component A and a component B, wherein the component A is prepared from waterborne epoxy resin, an iron red pigment, nano alumina, a dispersant, a filling material, a waterborne antifoaming agent, a waterborne preservative, negative ion distilled water and a waterborne amine curing agent; the component B is prepared from a waterborne epoxy resin emulsion, a waterborne antifoaming agent, a waterborne wetting and flatting agent, a waterborne preservative, a water-soluble active thinner and water. The component A and the component B adopted by the waterbornebicomponent epoxy iron red shop primer provided by the invention are both waterborne products, and are easily mixed; a sufficient curing purpose can be achieved. The waterborne bicomponent epoxy ironred shop primer has higher impact resistance, cannot generate foaming and stripping phenomena, meanwhile, has advantages of nontoxicity, flame retarding effect, explosion-proof effect, long application period, high hardness of film and high toughness, has uniform color and cluster, and can be used for meeting requirements of safety and environmental protection.