The invention relates to a water-based coating used for metal strip, is produced by evenly mixing epoxy modified polyester resin, cross-linking agent, pigment, curing catalyst and water. The excellent properties of the water-based coating are that the water-based coating can fast dry, has hard paint film with strong metal adhesion, and has good flexibility, solvent resistance and anticorrosion; the heavy metal content of the invention can reach ROHS environment protection standard. In addition, VOC content of the invention is low, thus eliminating pollution to environment. The invention pertains to environment-friendly products.