Abstract: 4-Piperidine lactone (PIL) was first synthesized by palladium carbon (Pd-C) catalytic hydrogenolysis using 4-acid benzyl piperidine lactone (NPIL) as the monomer. The cationic poly(4-piperdine lactone-co-caprolactone) (P(PIL-co-CL)) copolymers were further synthesized by enzyme or organometallics catalyzed ring-opening polymerization with benzyl alcohol as initiator, PIL and CL as monomers. The structure, molecular weight and thermal properties of copolymers were characterized by Nuclear Magnetic Resonance spectroscopy (¹H-NMR), Fourier Transform Infrared spectroscopy (FT-IR), Gel Permeation Chromatography (GPC) and Differential Scanning Calorimetry (DSC), etc. Results showed that the cationic P(PIL-co-CL) copolymers were synthesized successfully. Compared with organometallic catalyst Sn(Oct)₂, the immobilized enzyme Novozym 435 had the advantages of controllable polymerization and no side reaction.