Abstract: A 7-week feeding trial was conducted to evaluate effects of antimicrobial peptides-surfactin on intestinal health indices of genetically improved farmed tilapia (GIFT, Oreochromis niloticus). Three hundred and twenty fish with initial average weight of (12.010.12) g were randomly divided into four treatment groups with four replicates and 20 fish in each replicate. The fish were fed experimental diets supplemented with 0 (control group), 50, 100, and 200 mg/kg antimicrobial peptides-surfactin, respectively. Surfactin supplementation increased intestinal folds height of GIFT (P0.05) but did not impact the muscular thickness (P0.05). Surfactin supplementation significantly decreased the number of Escherichia coli of GIFT (P0.05) and significantly increased the number of Lactobacillus (P0.05). There was no significant difference in the total bacterial number among all treatment groups (P0.05). Surfactin supplementation significantly increased the total antioxidant capacity level and activities of glutathion peroxidase and superoxide dismutase (except 200 mg/kg Surfactin supplementation group) (P0.05) but significantly decreased the content of malondialdehyde (P0.05). Surfactin supplementation had no effect on catalase activity (P0.05). The intestinal health parameters of 50 mg/kg antimicrobial peptides-surfactin supplementation group were the best among all supplementation groups. In conclusion, surfactin supplementation at 50 mg/kg could improve intestinal health status of GIFT by increasing the intestinal folds height and regulating intestinal microbial population and antioxidant ability.