In this article, milled wood lignin (MWL) was isolated and purified from retted kenaf fiber, the lignin obtained was characterized by elemental analysis, FTIR, H-1-NMR, and C-13-NMR spectroscopy. The C-9 formula is calculated for kenaf fiber MWL as C9H9.32O3.69(OCH3)(1.30). The spectra of FTIR, H-1-NMR, and C-13-NMR show the kenaf fiber lignin to be of the G/S type with high proportion of syringyl (S) unit. The numbers of phenolic and aliphatic hydroxyl groups in the kenaf fiber MWL are estimated to be 0.1.4 and 1.31, respectively, per C-9 unit. The OHaliph is 90.3% in total numbers of hydroxyl groups of kenaf fiber MWL, and the OHph is 9.7%. It is evident that the beta-O-4 structures are mainly linkage in the MWL of kenaf fiber, which contain more erythro stereochemistry type in beta-O-4 units than thero stereochemistry type. In general, the characteristics of lignin of kenaf fiber are similar to that of hardwood. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 1896-1901, 2009