Abstract: Amphiphilic r-polyglutamic acid-g-β-cyclodextrin (γ-PGA-g-β-CD) copolymer was synthesized by esterification reaction between γ-polygluta-mic acid (γ-PGA) and β-cyclodextrin (β-CD). Its structure was characterized by Nuclear Magnetic Resonance Spectrometer (1H-NMR). The copolymer could self-assemble into colloidal particles and the particles were studied by Nanometer Particle Size Analyzer, and Atom Force Microscope (AFM). Then, the γ-PGA-g-β-CD colloidal particle solution was used as electrolyte. Combining with electrodeposition technique, nanostructured coating was prepared on the surface of magnesium alloy. The composition, morphology, and corrosion resistance of the coating were monitored using Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and corrosion test. Results show that the grafting degree of β-CD is 28%, and the diameter of γ-PGA-g-β-CD colloidal particles is (168±5.3) nm. The corrosion rate of magnesium alloy with γ-PGA-g-β-CD biological coating is reduced. The coating has a good protective effect.