Abstract: A novel block copolymer containing two polymeric components,poly(L-phenylalanine)-b-poly(L-aspartic acid) (PPA-PAA),was synthesized from N-carboxy-α-amino acid anhydride and its potential for the preparation of copolymer micelles with poorly water-soluble drugs was investigated in this study.The chemical structure and physical properties of PPA-PAA were characterized by FTIR and ¹H NMR.The degree of polymerization was calculated by analyzing the relative area of N-CH signal and C-CH₃ of ¹H NMR spectra.The critical micelle concentration (CMC) of the amphiphilic polymer was 95 mg/L.The amphiphilic polymer aggregation into 235 nm micelles.4-Amino-2-trifluoromethyl-phenyl retinate (ATPR) was studied as a poorly water-soluble model drug.The drug-loading and entrapment efficiency of the drug-loading micelles were 27.1% and 74.1%,respectively.In terms of the lower CMC and greater drug-loading capacity,the novel amphiphilic amino acid copolymer is a prospective delivery system for poorly water-soluble drugs.