A new aliphatic polycarbonate, terpolymer of carbon dioxide, propylene oxide, and dl-lactide, was synthesized by using a polymer-supported bimetallic complex as a catalyst. The terpolymer prepared was characterized by FT-IR, H-1 NMR, C-13 NMR, H-1-H-1 COSY, DSC, and WAXD measurements. The influence of molar ratio on the terpolymerization progress was investigated. The results showed that lactide unit was inserted into the backbone of CO2-PO successfully. Because of the existence of the lactide ester unit, the terpolymers had stronger degradability than poly(propylene carbonate).