In order to reveal the structural changes of hydrophobic starch- based film for food packaging during thecontact with food simulants,the microstructure,chain structure, intermolecular interaction,crystalline structureand micro- regional structure of the film were systematically analyzed by means of scanning electron microscopy,Fourier- transform infrared spectroscopy,as well as small and wide angle X- ray scattering technique.The results in-dicate that,along with the solvent permeation and the plasticizer migration occurring during the contact with foodsimulants,the macromolecular interaction of the film is enhanced; the microcrystallines aggregate; and the inter-planar spacing decreases,thus forming more compact aggregation structure and enhancing the molecular force exer-ted on the plasticizer.Moreover,it is found that the mobility of starch acetate macromolecules,the solvent permea-tion and the plasticizer migration are all retarded during the contact with food simulants.