The invention relates to a polymeric end-capping reagent for carbon dioxide-epoxide copolymers and a method for producing the same. The polymeric end-capping reagents provided by the invention are maleic anhydride copolymers and maleic anhydride terpolymers. The polymeric end-capping reagent for carbon dioxide-propylene oxide copolymers of the invention is produced by a radical solution copolymerization method, and has a number average molecular weight of Mn=4-6×104, a distribution index of 1.5-3.0. By using the polymeric end-capping reagent provided by the invention, the disadvantages of the small molecular end-capping reagent like volatilization during melting and precipitation on the melt surface during cooling, can be effectively overcome, moreover, the initial thermal decomposition temperatures of the carbon dioxide-propylene oxide copolymers end-capped with the polymeric end-capping reagents increase by about 30° C., as compared with that of the carbon dioxide-propylene oxide copolymer end-capped with “small molecular” maleic anhydride.