Polymeric micelles were prepared by dropping ethanol into solutions containing(poly(γ-benzyl L-)glutamate)-poly(ethylene oxide) block copolymer (PBLG-b-PEO),chloroform(CHCl3) and trifluoroacetic acid(TFA).Viscometry,transmission electron microscopy(TEM),nuclear magnetic resonance(()1H-NMR) spectroscopy and infra-red difference spectroscopy(IR) were used to investigate the influence of PBLG chain conformation on the self-assembly behavior of PBLG-b-PEO.The experimental results revealed that PBLG-b-PEO could associate into polymeric micelles in ethanol solutions.The introduction of TFA not only changes the conformation of PBLG segments,but also increases the critical micelle concentration,and further affects the morphologies of the formed micelles.