Cecal microbiota plays an essential role in chicken health. However, its contribution to fat metabolism, particularly in abdominal fat deposition, which is a severe problem in the poultry industry, is still unclear. Here, chickens at 1, 4, and 12 months of age with significantly (p< 0.05) higher and lower abdominal fat deposition were selected to elucidate fat metabolism. A significantly (p< 0.05) higher mRNA expression of fat anabolism genes (ACSL1,FADS1,CYP2C45, ACC, andFAS), a significantly (p< 0.05) lower mRNA expression of fat catabolism genes (CPT-1andPPARα) and fat transport geneAPOAIin liver/abdominal fat of high abdominal fat deposition chickens indicated that an unbalanced fat metabolism leads to excessive abdominal fat deposition.Parabacteroides,Parasutterella,Oscillibacter, andAnaerofustiswere found significantly (p< 0.05) higher in high abdominal fat deposition chickens, whileSphaerochaetawas higher in low abdominal fat deposition chickens. Further, Spearman correlation analysis indicated that the relative abundance of cecalParabacteroides,Parasutterella,Oscillibacter, andAnaerofustiswas positively correlated with abdominal fat deposition, yet cecalSphaerochaetawas negatively correlated with fat deposition. Interestingly, transferring fecal microbiota from adult chickens with low abdominal fat deposition into one-day-old chicks significantly (p< 0.05) decreasedParabacteroidesand fat anabolism genes, while markedly increasedSphaerochaeta(p< 0.05) and fat catabolism genes (p< 0.05). Our findings might help to assess the potential mechanism of cecal microbiota regulating fat deposition in chicken production.