The preparing methods, choice of catalysts and reaction kinetics of one of the monomers, diesteramide(DEA), of polyester-amides were investigated in details. The chemical structure of DEA was analyzed. And the Polyester-amides ( PEA) were obtained by melt copolymerization with DEA. It is shown that DEA can be synthesized by DMT and hexamethylene diamine with the catalyst EX - 1 or EX - 2. The relationship between reaction rate of synthesizing monomer and concentration of hexamethylene diamine is first order kinetic relation. The preparation methods, choice of catalysts and reaction kinetics of one of the monomers, diesteramide (DEA), of polyester-amides were investigated in details. The chemical structure of DEA was analyzed. And the Polyester-amides (PEA) were obtained by melt The relationship between reaction rate of synthesizing monomer and concentration of hexamethylene diamine is first order kinetic relation.