Abstract: Poly(vinyl chloride-co-vinyl acetate) containing carboxyl group was synthesized through aqueous suspension polymerization. Maleic anhydride (MAH) was esterified with ethanol to produce monoethyl maleate(MEM). The influence of reaction conditions, such as temperature and reaction time, on the yield rate of MEM was studied. MEM had amphiphilic property by solubility measurement. Terpolymer was prepared by reacting esterified MAH with vinyl chloride and vinyl acetate in terms of aqueous suspension polymerization method. With increasing MEM addition, the average particle size of synthesized copolymer was decreased. Meanwhile, the acid value of copolymer was obviously increased, and the coating adhesive force between polymer and aluminum sheet was improved. FTIR spectra showed that carboxyl group was introduced into the terpolymer successfully.