Objective To investigate the effects of different processes on the functional activity of polyphenols in acorn powder.Methods Three different types of acorns, namely acorns, Cyclobalanopsis, and Castanopsis sclerophylla, are used as raw materials to prepare acorn powder by water leaching and enzymatic hydrolysis methods. Polyphenols are extracted from acorns and acorn powder. Then, polyphenol extracts from acorn powder treated by different processes and from acorns are compared according to the aspects below: free radical scavenging activity, lipoxygenase (LOX) and cyclooxygenase-2 (COX-2) inhibition, as well as anti-intestinal inflammation activities.Results With relatively high free radical scavenging activity, the polyphenol extracts from acorn powder exhibit ideal inhibition activities against LOX, COX-2, and Drosophila enteritis. The polyphenol extracts from acorn powder prepared by enzymatic hydrolysis are better in anti-enteritis effect. Especially, the polyphenol extracts from C. sclerophylla by enzymatic hydrolysis exhibit the highest inhibition activities against LOX, COX-2, and Drosophila enteritis, which are (95.54±0.31)%, (80.62±1.49)%, and (74.36±11.70)%, respectively.Conclusion The antioxidant and anti-enteritis effects of the polyphenol extracts from the acorn powder by enzymatic hydrolysis are stronger than those from the acorn powder by water leaching.