Poly(D,L-lactide) macromonomers with the functional end double bond were first prepared by bulk ring-opening polymerization of D,L-lactide (D,L-LA) (using) stannous 2-ethyl hexanoate (Sn(Oct)₂) as a catalyst,and 2-hydroxyethyl methacrylate (HEMA) as a co-initiator.Then,the amphiphilic graft copolymers from methamonomers and N-vinyl pyrrolidone (NVP) were obtained by solution free radical copolymerization,the effects of the co-monomer molar ratio and the length of the polylactide (PLA) branched chain on the properties of the copolymers were preliminary studied.Results showed that the tensile strength and modulus of the copolymer membrane increased,while the hydrophilicity was somewhat decreased with increasing molar content of methamonomer and the length of PLA branched chain.