In order to develop flour food with low digestibility and study the effect of Quercus variabilis Bl. acorn shell extract on wheat starch properties. Quercus variabilis Bl. acorn shell was taken as raw materials in this study， and extracted by ultrasonic assisted ethanol extraction. Subsequently， the functional components of the ethanol extract were analyzed by HRLC-MS， and its effects were determined on the gelatinization properties， gel properties and digestion properties of wheat starch by comparative test and in vitro simulated digestion test. The results showed that the yield of ethanol extract was 2.40%， Quercus variabilis Bl. acorn shell， in which the total phenol content was 102.87 mg GAE/g and the total flavonoid content was 41.72 mg RE/g. By HRLC-MS， 34 components were detected， including polyphenols， flavonoids， terpenes， organic acids and other active components. The ethanol extract could significantly reduce the gelatinization viscosity and thermal stability of wheat starch， as well as some gel properties (i.e. elasticity， hardness， chewiness， and viscosity)， made surface rougher and the organizational structure looser， and inhibit the aging of wheat starch gel. After the addition of 15% ethanol extract of Quercus variabilis Bl. acorn shell， the digestibility reduced by 38.16% by 20 min of in vitro simulated digestion. Conclusion: The ethanol extract of Quercus variabilis Bl. acorn shell contains abundant functional components， which could change the gelatinization properties and gel structure of wheat starch， reduce the digestibility of wheat starch， and could be combined with wheat starch to develop low-digestibility flour products.