Abstract: In order to improve the digestibility, bioaccessibility and antioxidant properties of oat enzyme powder, the oat enzyme powder was prepared after processing of oats, the β-glucan content, bioaccessibility, and the changes of starch digestibility and antioxidant activity were investigated. The results showed that after extrusion puffing, the content and bioavailability of β-glucan in oat enzyme powder increased by 13.89% and 10.80 percent points, respectively,the digestibility of starch improved, among which, the content of rapidly digested starch and slowly digestible starch increased by 1.43 percent points and 5.89 percent points, respectively, while the resistant starch content decreased by7.32 percent points, the content of both amylopectin and amylose decreased. The antioxidant properties of oat enzyme powder also improved, among which the ability for scavenging DPPH, ABTS and hydroxyl free radicals increased by29.17%, 16.35%, and 16.07%, respectively, and reducing power increased by 21.29%. Which indicated that the extrusion puffing technology could improve the digestibility of starch, bioaccessibility of β-glucan and antioxidant activity,and nutritional value of the oat enzyme powder.