Poly(D,L-lactide)-poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(epsilon-caprolactone) -poly (D,L-lactide) block copolymer (PLA-PCL-PEG-PCL-PLA) was prepared by copolymerization of epsilon-caprolactone (epsilon-CL) and D,L-lactide (D,L-LA) initiated by potassium poly(ethylene glycol) ate in THF at 25 degrees C. The copolymers with different composition were synthesized by adjusting the mole ratio of reaction mixture. The resulted copolymers were characterized by H-1-NMR, C-13-NMR, IR, DSC, and GPC. Efforts to prepare copolymers with the corresponding structure of PCL-PLA-PEG-PLA-PCL and D,L-lactide/epsilon-caprolactone random copolymers were not successful.