Abstract: The influence of extrusion processing temperature, screw speed, material moisture content on antioxidant activity, polyphenol content and the form of millet were studied, and the correlation between total phenols, flavonoids and antioxidant capacity and the change was analyzed. The results showed that effect of extrusion processing temperature, screw speed, material moisture content on antioxidant activity, polyphenol content and the form of millet were most significantly different in millet, but the temperature had little effect on the free flavonoid, and screw speed had no significant effect on the bound phenol. Total phenol and flavonoids content in millet had significant correlation with antioxidant capacity (p<0.01) . In a word, extrusion processing was beneficial to keep the polyphenols in millet and was an effective way of processing.