In this study, acrylic acid modified epoxy resin containing terminal double bond with the partial retention of epoxide group was synthesized. A stable waterborne epoxy-acrylate composite emulsion containing modified epoxy resin acrylate polymer (core) –inerent polyacrylate (intermediate layer) -carboxyl acrylate polymer (shell) was successfully prepared by emulsion copolymerization and characterized by structural design. And the corrosion resistance of the composite latex films was studied. The results showed that (1) there is successful emulsion copolymerization between modified epoxy resin and acrylate monomer, and the obtained composite emulsion has the partial retention of the epoxide group and the introduced carboxyl group.(2) The stability and corrosion resistance of the three-layer composite emulsion with the intermediate layer are better than those of the conventional core-shell emulsion, and the set intermediate layer can indeed play an expected role.(3)The mass fraction of intermediate layer has great influence on the corrosion resistance of coatings. When the mass fraction of intermediate layer was 26%, the thickness of the middle layer calculated by temperature random multi-frequency modulation DSC technology was 14.51 nm, the value of |Z|0.01Hzwas 1.66×104 Ω?cm2of the three-layer core-shell coatingsafter7days immersion of 3.5 wt% NaCl solution, and the content of iron on tinplate remained 95.29%after the samples were immersed in 3.5wt% NaCl solution for 30 days, the coatings were peeled off to expose the steel surfaces.