Novel maleic anhydride (MA H), ethylene glycol oligomer-modified poly(D,L-lactide acid) (PEMLA), and crosslinked-PEMLA were synthesized via a series of chemical bulk modification. Briefly, MAH copolymerized with ethylene oligomer [EGO (including EG, PEG200, PEG400)] to give the PEMA; thereafter, D,L-lactide (DLLA) and prepolymers (PEMA) copolymerized to produce the PEMLA; at last, the crosslinked-PEMLA was synthesized by free radical reaction of the PEMLA. The characterization of PEMLA and crosslinked-PEMLA showed that the introduction of hydrophilic group -O- and -CH=CH- increased the flexibility and hydrophilicity of PDLLA. Moreover, the degradation of PEMLA and crosslinked-PEMLA were determined by molar weight changes and weight loss rate, and a special method, analysis of degradation positions via H-1-NMR, which indicated that the PEMLA and crosslinked-PEMLA have nice degradation, and the change of content of MAH, EGO can regulate the degradation rate of PDLLA. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 3460-3470, 2010