Abstract: In order to study the antioxidant activity in vitro of soluble dietary fiber from jujube, the contents of total flavonoids and total polyphenols of soluble dietary fiber from jujube were determined by the Na NO₂-Al (NO₃) ₃-Na OH method and Folin-Ciocalteu method, respectively.In addition, the antioxidant activities of soluble dietary fiber from jujube were evaluated by antioxidant methods, including DPPH radical scavenging capacity, ABTS radical scavenging capacity, hydroxyl radical scavenging capacity, superoxide anion radical scavenging capacity, hydrogen peroxide radical scavenging capacity and reducing power.The results showed that the contents of total flavonoids and total polyphenols of the soluble dietary fiber from jujube were (1.78±0.04) mg/g and (4.12±0.09) mg/g, respectively.The soluble dietary fiber from jujube had good antioxidant activity in vitro.It had good scavenging capacity on DPPH radical and hydrogen peroxide radical, at 2.0 mg/m L, their scavenging capacities could reach respectively 79.81%and 50.07%, and scavenging capacities on DPPH radical were strongest, IC₅₀was 0.725 mg/m L.The scavenging capacities on ABTS radical, hydroxyl radical and superoxide anion radical were weaker, and it had certain reducing power.It was indicated that the soluble dietary fiber from jujube has certain the antioxidant activity in vitro, and it can be used as an effective natural antioxidant and develop functional food of dietary fiber from jujube.