Objective: This study aimed to determine the effects of compatibility of <i>Clostridium butyricum</i> and <i>Bacillus subtilis</i> on growth performance, lipid metabolism, antioxidant status and cecal microflora of broilers during the starter phase.Methods: A total of 600 1-day-old Ross 308 broilers were randomly divided into two groups with six replicates in each group. Chickens in the control group were fed a basal diet, while chickens in the experimental group were fed a diet supplemented with 2×10<sup>8</sup> colony forming units (CFU)/kg of <i>C. butyricum</i> and 1×10<sup>9</sup> CFU/kg of <i>B. subtilis</i>. The experimental period was 21 days.Results: Addition of <i>C. butyricum</i> and <i>B. subtilis</i> significantly increased (p<0.05) the body weight and liver nicotinamide adenine dinucleotide phosphate-malic enzyme (NADP-ME) activity of broilers, enhanced (p<0.05) the average daily gain and average daily feed intake of broilers. However, the addition of <i>C. butyricum</i> and <i>B. subtilis</i> did not significantly affect the concentrations of triglyceride and total cholesterol in the serum, the activities of fatty acid synthase and acetyl–CoA carboxylase in the liver, the total antioxidant capacity, glutathione peroxidase activity and malondialdehyde content in the serum and liver. Besides, microbial analysis revealed that supplementation of <i>C. butyricum</i> and <i>B. subtilis</i> increased (p<0.05) the abundance of <i>Firmicutes</i> such as <i>CHKCI001</i> and <i>Faecalibacterium</i>, decreased (p<0.05) the abundance of <i>Bacteroidota</i> such as <i>Bacteroides</i> and <i>Alistipes</i>. Spearman correlation analysis confirmed that the above cecal microbiota were closely related to the growth performance of broilers (p<0.05). In addition, simultaneous supplementation of <i>C. butyricum</i> and <i>B. subtilis</i> significant affected (p<0.05) 33 different functional pathways such as lipid metabolism and carbohydrate metabolism. This explains the phenomenon of increased growth performance and liver NADP-ME activity in the probiotics group.Conclusion: The compatibility of <i>C. butyricum</i> and <i>B. subtilis</i> could improve the growth of broilers during the starter phase by changing the cecal microflora.