An aliphatic polycarbonate, terpolymer of carbon dioxide, propylene oxide and epsilon-caprolactone(PPC-CL-PPO-CL), was synthesized by using a polymer supported bimetallic complex as a catalyst. The terpolymers prepared were characterized by FTIR, H-1 NMR, C-13 NMR, DSC and WAXD measurements. The influences of various reaction conditions such as molar ratio of the monomers, reaction time and reaction temperature on the terpolymerization progress were investigated. The results showed that epsilon-caprolactone (epsilon-CL) was inserted into the backbone of poly( propylene carbonate)-poly(propylene oxide) (PPC-PPO) successfully. The viscosity and glass transition temperature of the terpolymers were much higher than PPC-PPO. epsilon-Caprolactone offered an ester structural unit that gave the terpolymers remarkable degradability. And the degradation rate of the backbone increased with the epsilon-CL inserted into the terpolymers.