To detect the gut colonization capacity of CCFM1025 with clinical antidepressant-like effects. A unique gene sequence of CCFM1025 was discovered based on the genome analysis of 104 strains and a strain-specific primer (1025T5) was designed. and samples were used to validate the specificity and quantitative capability of this primer in the PCR system. Quantitative PCR using strain-specific primers enabled absolute quantification of CCFM1025 in fecal samples within 10-10 cells/g (R >0.99). CCFM1025 remained highly detectable in volunteer feces 14 days after cessation of administration, demonstrating its favorable colonization characteristics. CCFM1025 can colonize the healthy human gut.