Abstract: The invention discloses a method for the detection of sialate glycosyl casein glycomacropeptide by boronate affinity column enrichment-liquid chromatography-tandem mass spectrometry using phenylboric acid modified mesoporous silica as packing material, which belongs to the field of food analysis and detection. The method includes the following steps: (1) sample preparation; (2) enrichment and purification of boronate affinity column; (3) liquid chromatography-tandem mass spectrometry detection. The invention makes use of the affinity property of phenylboric acid to the special sugar group sialic acid on the serine and threonine residues in casein glycogiant peptide, regulates the adsorption and elution of casein glycogiant peptide with sialic acid group by changing pH.