In this paper，the epoxy phosphate ester resin（EPER） was obtained bycovalent bond grafting of diethyl phosphate（DPA）and epoxy resins，which was used as the matrix resin to prepare the cured varnish coating. The composition，construction，glass transition temperature of EPER，and the interior morphology，mechanical properties，and anti-corrosion properties of cured coating were characterized by FT-IR， ¹H NMR，XPS，DSC，SEM，and EIS. The DPA content and epoxy value on the intrinsic properties of the cured coatingwere studied systematically. The results showed that the modified EDPA increased themechanical properties of the cured coating on one hand，and on the other hand enhanced the corrosion resistance of the cured coating due to the chelation of phosphate and metallic ions， which made it possible to be applied in the field of metal protection.