Abstract: Preparation of radiation modified starch by double irradiation of 60Co-γ ray and microwave. To test the gelatinization temperature and solubility of radiation modified starch, compared with the corn native starch and H2O2 oxidized starch, modification with γ radiation and microwave can also improve the gelatinization temperature and solubility of starch, and lowering the viscosity. Were determined the content of amylose and amylopectin with Butanol Sedimentation, the results show that, the degradation rate of amylopectin was 30.9 %. So the starch to exist as the main linear amylose after γ radiation and microwave, better able to dissolve in hot water for the formation of true solution.