Objective： UPLC-MS technology was used to study the metabolic characteristics of fermented milk during storage， and the quality of fermented milk during storage was evaluated by the perspective of metabolisms， which in order to provide effective basis for industrialized production and control the quality of S. thermophilus S10 fermentation milk. Method： Collected fermented milk for 0， 1， 7， 14， 21 d of storage. The metabolic fingerprint of fermented milk was established based on ultra high performance liquid chromatography - quadrupole time of flight mass spectrometry （UPLC-QTOF MS）. The data were preprocessed with the software MarkerLynx， and analyzed by principle component analysis， and orthogonal signal correction partial least squares discrimination analysis. Results： Potential biomarkers were screened out according to database searching and MS information matching. A total of 22 metabolites including Glycyl-L-valine， succinic acid， oxaloacetate， glycine， L-glutamic acid， nicotinic acid were identified inset fermented milk during different storage times. These potential biomarkers relate to several metabolic pathways such as carbohydrate and energy metabolism， nucleotide metabolism and amino acid metabolism. Conclusion： The differential metabolites involved in the metabolic characteristics of S. thermophilus S10 fermented milk were mostly primary metabolites， which type and content do not have an adverse impact on the quality of the fermented milk.