The fermented milk is considered as a complex food system， measurement of all metabolites in fermented milk using a single analytical platform is usually unattainable. Fermented characteristics was investigated， and metabolites profile of Lactobacillus plantarum P-8 in strain-dependent fermentation and co‐fermentation with commercial starters YC-X11 was analyzed by ultra-performance liquid chromatography- quadrupole-time of flight mass spectrometry （UPLC-Q-TOF） combined statistical methods. When the single strain of Lactobacillus plantarum P-8 was used in the fermentation， the time to reach the end point was 13 hours. The fermentation time required 5 hours with both Lactobacillus plantarum P-8 and commercial starter YC-X11. During the fermentation process， the bacterial viable counts in different fermented milk significantly increased （P ＜ 0.05）， and the titratable acidity significantly increased （P ＜ 0.05）. 62 metabolites were determined as the major compounds contributing to the discrimination of fermented milk. The different metabolites between the mixed fermented milk and the fermented milk with Lactobacillus plantarum P-8 were organic acid （7 species）， polypeptide （4 species）， free amino acid （4 species）， nucleic acid metabolites （4 species） and aromatic substance （3 species）. Therefore， metabolomic methods can be used to identify and analyze different metabolites in fermented milk， which could serve as potential biomarkers.