Three derivatizing agents （2-aminobenzoic acid， 2-aminobenzamide and 2-aminoacridone） were compared and 2-aminobenzoic acid was selected as the optimal derivatizing agent. Based on that， an ultra-performance liquid chromatography-tandem mass spectrometry method was developed to quantitatively detect the contents of 6 human milk oligosaccharides （HMOs） in human milk. After degreasing， deproteinizing， and derivatizing 2-aminobenzoic acid of the sample， the samples were separated on an ACQUITY UPLC BEH Amide column， and the content of HMOs was quantitatively determined by multi-reactive ion monitoring （MRM） mode. Methodological verification results show that the linear relationship of each HMO is favorable within the set concentration range， and the correlation coefficient is greater than 0.99. In the high， medium and low level fortification experiments， the recovery rate is between 83.2%-119.9%， the intra-day precision is between 1.0%-7.9%， and the inter-day precision is between 4.5%-7.4%. The limitation of quantitation （LOQ） of 2'-fucosyllactose， 3'-fucosyllactose is 1.5 mg/L， and the LOQ of 3'-sialyllactose， 6'-sialyllactose， lacto-N-fucopentaose-I is 5.0 mg/L， lacto-N-fucopentaose-V has a LOQ of 4.5 mg/L， which indicate a good sensitivity. The precision and accuracy of the method are good， which meet the precise quantitative requirements of 6 HMOs in human milk.