Alkaline extraction was used to extract waterunextractable arabinoxylan (WUAX) and waterextractable arabinoxylan (WEAX) from wheat bran. The bile salt binding capacity and pancreatic lipase inhibitory activity of WUAX and WEAX were investigated to reveal the effects of wheat bran arabinoxylan (AX) with different types of structure on lipid reduction in vitro. The results showed that the binding rate of WEAX to bile salt was less than 15%,and the binding capacity of WUAX to bile salt was stronger than that of WEAX. The binding rate of WUAX to sodium taurocholate hydrate and sodium glycocholate hydrate was 52.87% and 38.30%,respectively. The Freundlich equation was used to fit the isothermal adsorption curves,and the 1/n of WUAX to sodium taurocholate hydrate and sodium glycocholate hydrate was 0.51 and 1.30,respectively,indicating that compared with sodium glycocholate,WUAX bound to sodium taurocholate more tightly. Contrary to the binding capacity of bile salt,WEAX had a significantly higher inhibition rate on pancreatic lipase than WUAX. The inhibition rate of WEAX on pancreatic lipase increased with the increase of the concentration,with the highest inhibitory rate of 35.93% when the concentration was 30 mg/mL. The results of the reaction rate curve and the LineweaverBurk curve showed that the inhibition of pancreatic lipase by WEAX was reversible,and the type of inhibition was mixed inhibition. In summary,there are difference in the effect of WUAX and WEAX on lipid reduction in vitro,which is related to the difference in the characteristics of structure. It will provide practical reference and theoretical support for further studying the mechanism of lipid metabolism regulated by AX.