Abstract: Acrylateaniline copolymerization emulsion was synthesized with a two-step emulsion polymerization, and characterized by Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and transmission electron microscope (TEM), etc. The surface of Q235 mild steel was coated by the copolymerization emulsion, and then the anticorrosion properties of the copolymerization emulsion coating to Q235 mild steel were investigated by electrochemical impedance spectroscopy (EIS), Tafel polt and open circuit potential (OCP). Results show that the acrylate emulsion doped the polyaniline effectively as acid because of production of chemical bonds between aniline and acrylate emulsion. The film forming ability of copolymerization emulsion was better. Copolymerization emulsion coatings had better corrosion resistance performance: the impedance was higher (3.0×105 Ω·cm2), the corrosion current density was lower (10-8 A/cm2), and the anticorrosion potential of coatings was improved (-0.44 V).