Abstract: In order to understand the effect of different alcohol contents (30%~100%) on starch structure and physicochemical properties under ultra-high-pressure field (200, 400, 600 MPa), changes of starch multi-scale structure and physicochemical characteristics were investigated. Related techniques such as scanning electron microscopy, small-angle X-ray scattering, X-ray diffraction and rapid viscosity analysis were applied for evaluating how pressure fields and alcohol content affected the granular structure, lamellar structure, crystalline structure, pasting and retrogradation behaviors of starch. Results showed that, starch granular, lamellar and crystalline structures were severely disrupted under 600 MPa pressure and pure water solution, and the peak viscosity of starch gradually decreased. And the alterations from starch ordered structure to its disordered form were significantly inhibited with the increased alcohol content (30%~100%), whereas its peak viscosity displayed an irregular trend. Furthermore, the alcoholic component in the solution during ultra-high pressure treatment could significantly delay the aging behavior of starch paste. In summary, this research would provide theoretical guidance for rationally controlling the starch structure and functional properties based on ultra-high-pressure with different solution polarity.