Exposure to chemical pollutants and their effects on the gut microbiome during early life are scarce, especially the effects of mixed exposures. Plasma pollutants levels were measured using gas chromatography -triple quadrupole mass spectrometer (GC-MS/MS) among 304 infants in the neonatal ward at Hunan Children's hospital, China, and gut microbiota was derived from 16S rRNA sequencing. We assessed exposure and alpha diversity using generalized linear models, and variation in beta diversity (Bray-Curtis), taxa abundance (MaAsLin2), and employed Bayesian kernel machine regression (BKMR) to investigate the association of pollutants mixture with alpha diversity and taxa. PBDE-99 was positively associated with the Chao1 index (β = 4.29, 95%CI:1.54,7.03). Exposure to the pesticides trifluralin, γ-BHC, and methidathion significantly affected beta diversity (all P