Xylo-oligosaccharides were prepared from Camellia oleifera shell via hydrothermal treatment after electron beam irradiation. The antioxidant activity of xylo-oligosaccharide of Camellia oleifera shell after decolorization was determined and analyzed through optimizing the decolorization process of activated carbon. This provides a new approach for the high-value utilization of by-products from Camelliaoleiferaprocessing. The results showed that the concentration of xylo-oligosaccharides prepared via 3 MeV electron beam irradiation combined with hydrothermal treatment was 13.87 mg/mL, and the concentrations of xylobiose to xylotetrose after enzymolysis were 3.37 mg/mL, 4.76 mg/mL, and 2.48 mg/mL, respectively. The optimization process of activated carbon decolorization as follows: the decolorization efficiency of Darco G60-activated carbon for xylo-oligosaccharides enzymolysis solution of the Camellia oleifera shell reached 93.77% at a decolorization temperature of 30 ℃, a decolorization time of 60 min, an activated carbon addition of 50 mg/mL, and a pH of 4. The retention rates of xylobiose to xylotetrose and total xylo-oligosaccharides were 97.66% and 71.50%, respectively. It was found that the xylo-oligosaccharides of the Camellia oleifera shell were amorphous and cross-linked with several parts, as shown by scanning electron microscopy and Fourier transform infrared spectroscopy, with the main chain formed by D-xylose via β-1,4-glucoside linkage. In addition, when the concentration of xylo-oligosaccharides in Camellia oleifera shell was 10 mg/mL, the antioxidant activity was better. The scavenging rates of 1,1-Diphenyl-2-picrylhydrazyl(DPPH) radical, 2,2'-Azinobis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) radical, superoxide anion and hydroxyl radical were 62.07%, 68.50%, 70.26% and 75.52%, respectively.