Abstract: In order to study the functions and mechanisms of the postbiotics derived from composite probiotics, this study focused on the postbiotics produced by the co fermentation of Lacticaseibacillus paracasei ProSci-101 and Bifidobacterium adolescentis B8589. Metabolomics techniques were used to analyze the beneficial metabolites of the postbiotics. The results showed that the antibacterial and antioxidant abilities of the postbiotics derived from composite probiotics were significantly (P<0.05) stronger than those of single strain fermentation postbiotics. Metabolomics analysis showed that there were 159 and 161 differential metabolites in the postbiotics derived from composite probiotics compared to the postbiotics derived from ProSci-101 and B8589 single strains, respectively. The differential metabolic pathways were mainly amino acid and glycerophospholipid metabolism. postbiotics derived from composite probiotics are enriched with beneficial metabolites such as alkaloids, flavonoids, and organic acids. The study provides a theoretical basis for the development and application of postbiotics derived from composite probiotics.