Objective To purify and enrich the distiller's grain polyphenols (DGPs) with good antioxidant activity.Methods Organic solvent extraction combined with macroporous adsorption resin was used to enrich and recover DGPs from the distiller's grains deep eutectic solvent (DES) extraction solution. The purity and antioxidant activity of the purified products were determined. Extraction solvents and resin types were screened, and adsorption kinetics, isotherms, and thermodynamics were used to explain the adsorption mechanism. The optimal process conditions were determined. The in vitro antioxidant activity of the polyphenols was evaluated by measuring their ability to scavenge 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) free radicals and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) free radicals.Results Dichloromethane was the most suitable extraction solvent, with a polyphenol recovery rate of 90.83% when the ratio of dichloromethane to DES was 2∶1. The best resin for purifying DGPs was DM130, with an adsorption rate of 78.70%. The adsorption of DGPs by DM130 resin conformed to pseudo-second-order kinetics and the Langmuir adsorption model, indicating that the process is spontaneous and exothermic. The optimal purification conditions with DM130 resin were a sample solution pH of 5, a sample concentration of 0.8 mg/mL, a flow rate of 2 BV/h, a sample volume of 3.4 BV, and elution with 60% ethanol at a flow rate of 3 BV/h and an elution volume of 6.9 BV. The overall recovery rate of DGPs from the distiller's grains DES extraction solution after dichloromethane extraction and DM130 resin adsorption was 88.90%, with polyphenol purity increasing from 2.11% to 16.05%. Seven phenolic compounds were detected in the purified product, with ferulic acid being the most abundant. The IC₅₀ values for scavenging DPPH and ABTS⁺ free radicals were 0.080 4 mg/mL and 0.185 0 mg/mL, respectively.Conclusion The purification method for the DGPs established in this study is effective and feasible, and the enriched DGPs exhibit good antioxidant activity.