Abstract: The effect of combined treatment of cellulase and superfine grinding on the physicochemical properties, including particle size analysis, content of damage starch, pasting properties, swelling power, solubility, and in vitro antioxidant properties, as well as microscopic structure, of whole Tartary buckwheat flour was systematically evaluated in this study. The results showed that cellulase treatment significantly increased the content of soluble dietary fiber and reduced the content of insoluble dietary fiber in whole Tartary buckwheat flour (P<0.05). Compared to the untreated whole Tartary buckwheat flour, both the superfine grinding treatment and the combined treatment significantly diminished its particle size (P<0.05). Additionally, the particle size of the samples continuously decreased as the classifier frequency increased. The combined treatment resulted in significantly smaller particle sizes than superfine grinding alone (P<0.05). As the classifier frequency increased, the content of damaged starch in whole Tartary buckwheat flour significantly raised (P<0.05), and its swelling power and solubility were also notably enhanced. The superfine grinding treatment and the combined treatment notably altered the pasting properties of whole Tartary buckwheat flour. The results of in vitro antioxidant experiments demonstrated that the superfine grinding treatment facilitated the extraction of free polyphenols and flavonoids in whole Tartary buckwheat flour, thereby markedly enhancing its antioxidant capacity (P<0.05). Furthermore, samples treated by combined treatment exhibited superior in vitro antioxidant capacity compared to the samples treated by superfine grinding treatment. Both superfine grinding treatment and combined treatment caused varying degrees of damage to starch granules of samples observed by SEM. The findings of this study would provide a theoretical foundation for the modification of whole Tartary buckwheat flour and the development of whole Tartary buckwheat foods.