Objective To investigate the effects of extrusion technology on the physicochemical properties, digestion characteristics, and nutritional components of sea red rice.Methods The extrusion process parameters for sea red rice are optimized by response surface methodology. The effects of the extrusion treatment on the physicochemical properties of the sea red rice flour are explored by water solubility index (WSI), gelatinization degree, starch digestion properties (including rapidly digestible starch, slowly digestible starch, and resistant starch), and the anti-nutritional factor content (phytic acid). The microstructure, starch crystal form, and crystallinity are characterized before and after extrusion.Results After extrusion treatment, the water solubility (WSI) of 18.48% and gelatinization degree (95.35%) are improved in the sea red rice flour. The starch crystal form of sea red rice flour is changed from A type to V type, the crystallinity is decreased by 56.44% (P<0.01), and the viscosity coefficient and gelatinization peak temperature are decreased significantly. Additionally, extrusion reduces the content of phytic acid, an antinutritional factor in sea red rice flour, by 18.83% (P<0.01), while increasing the rapidly digestible starch proportion and reducing the resistant starch content, with in vitro starch digestibility increased to 74.72%.Conclusion Extrusion technology significantly improves the physicochemical properties of sea red rice, reduces the anti-nutritional factor contents, and effectively retains its nutrients, improving the digestion characteristics of starch.