Novel amphiphilic triblock copolymer poly(p-dioxanone-co-5-benzyloxytrimethylene carbonate)-block-poly(ethylene glycol)-block-poly(p-dioxanone-co-5-benzyloxytrimethylene carbonate) (p(PDO-co-BTMC)-b-PEG-b-p(PDO-co-BTMC)) was successfully synthesized using immobilized porcine pancreas lipase on porous silica particles (IPPL) as the catalyst for the first time. 1H NMR, 13C NMR and GPC analysis were used to confirm the structures of resulting copolymers. The molecular weight (Mn) of the copolymer with feed ratio of 69:20:11 (BTMC:PDO: PEG ) was 31300 g/mol and the polydispersity was 1.85, while the Mn decreased to 25000 g/mol and polydispersity of 1.93 with the feed ratio of 50:40:10.