Abstract: The ternary emulsion copolymerization of two hydrophobic monomers, octadecyl acrylate and dodecyl and the hydrophilic monomer, acrylic acid was realized by using cyclodextrin as the solubilizing carrier of acrylic long chain esters, aiming at improving the comprehensive performance of the retanning and fatliquoring agent of amphiphilic polymer. The structure and molecular weight of the polymer were characterized by FTIR and GPC, the basic properties of the amphiphilic polymer emulsion were measured, and the application effects of the copolymer on retanning and fatliquor were also investigated. The results showed that the target product was successfully synthesized, and the emulsion had good stability. The number average molecular weight of the product was about 4000. It could penetrate well into the leather. The ternary copolymer had?ideal retanning and fatliquoring effect, and the treated leather had high softness, good static waterproofness. The absorption rate was up to 98.41%, which could greatly reduce COD in waste liquid.