Abstract: The objective is to establish the HPLC-ELSD detection method of xylooligosaccharide in brewer''s enzymatic hydrolysis. Brewer''s grains hydrolysate was extracted with pure water, chromatographic column was COSMOSIL Sugar-Danalytical column (250 mm×4.6mm, 5 μm), the mobile phase was acetonitrile-water (69: 31, V/V), the flow rate was 0.9 mL/min, the column temperature was 40℃, the injection volume was 3 μL, the evaporator temperature was 78℃, flow rate of carrier gas was 1.6 L/min and carrier gas pressure was 0.5 MPa, and the content of xylooligosaccharide was determined by using the peak area external standard method. The results showed that Xylobiose-Xylopentaose had good linear relation in the range of 0.024-0.245 mg/mL, the detection limits were 0.0245, 0.0245, 0.02425, 0.024 mg/mL, and the limits of quantification were 0.0907, 0.0907, 0.08981, 0.8889 mg/mL. The relative standard deviations (RSD) were 0.203%, 0.224%, 0.233% and 0.252% and the spiked recoveries rates were 97.31%-99.83%. The results indicated that this method had a high sensitivity and good repeatability and could be applied to detect xylooligosaccharide in brewer''s grains.