With L-glutamic acid as raw materials, N-carboxy-L-glutamic acid-benzyl-anhydride (BLG-NCA) was synthesized by triphosgene. With aniline as the initiator in the anhydrous dichloromethane, ring-opening polymerization of BLG-NCA was initiated, poly-l-glutamic acid benzyl ester was obtained. The amount of initiators, Molar ratio of monomer/initiators, reaction temperature and reaction time to the effect of poly-l-glutamic acid benzyl ester in the ring-opening polymerization of BLG-NCA were studied. Through infrared spectroscopy, gel permeation chromatography (GPC) analysis and characteristic viscosity method, polymerization product was characterized and analysized. Results showed that in dichloromethane, ring-opening polymerization of BLG-NCA could be initiated by aniline, which expands greater scope of the initiators of poly-l-glutamate to aromatic compounds, and the introduction of the active group provided by aromatic compounds make it possible for the advanced development of block copolymer with poly-l-glutamic acid as a basic unit.