Abstract: A rapid identification and determination method of chemical components in industrial maltooligosaccharide was established by HILIC-ELSD-ESI-Q-TOF/MS technology. Taking maltooligosaccharide as the research object, the rapid separation of maltooligosaccharide was carried out by HILIC method, and a variety of compounds were identified by ESI-Q-TOF/MS method. Based on the accurate molecular weight, MS/MS fragmentation characteristics, chromatographic retention behavior and other information, combined with reference material information and literature reports, the known components were quantitatively determined by HILIC-ELSD. The results showed that the separation of the components in maltooligosaccharide was good by hydrophilic chromatography. Ten components in maltooligosaccharides were identified by ESI-Q-TOF/MS, the correlation coefficients of the regression equations of the seven compounds(glucose, maltose, maltotriose, malttetrasaccharide, maltpentasaccharide, malthexose, maltohexaose) were all better than 0.9990, indicating a good linear relationship. The average recoveries were in the range from 95.66% to 99.00% with relative standards deviation between 1.11% and 4.93%. The limits of detection ranged from 0.004 to 0.070 μg/mL and limit of quantitation between of 0.013~0.233 μg/mL. The quantitative determination of seven components showed that the content of maltose was the highest(14.31%±0.13%), followed by maltotrisaccharide(9.34%±0.14%) and maltohexose(7.49%±0.09%). The total contents of maltose, maltotrisaccharide, maltotrisaccharide, maltopentose, maltohexose and maltoheptoglycose reached 43.39%±0.35%. The method had good resolution and high sensitivity, and could be used for qualitative and quantitative analysis of maltose with different degree of polymerization. It provides an analytical method support for the industrial production and application of maltooligosaccharides.