A catalyst for the copolymerization of CO2 and cyclohexene oxide was prepared by using acetylacetone and 4,4'-methylenedianiline. The catalyst was characterized as composed of a novel structure of the polymeric diimide Zn complex. The catalyst tended to produce an alternative copolymer with efficiency as high as 128 g polymer/g of catalyst. The obtained copolymers were characterized by IR and NMR. Effects of reaction conditions such as reaction time and temperature, CO2 pressure, and catalyst concentration on copolymerization were investigated. Best results were obtained from the reaction at 90 degreesC for 24 h, with catalyst concentration of 0.13 g/mL, and CO2 pressure of 2-3 MPa.