Abstract: To evaluate the gastrointestinal effects of Amomum villosum essential oil on promoting digestion and protecting intestine tract in breeding of Oreochromis niloticus, we fed the juveniles (20.34±2.08) g with basic diets of 0 (Control group), 2 (Low-dose group), 4 (Medium-dose group) and 8 g·kg⁻¹ (High-dose group) of A. villosum essential oil for 8 weeks. The results show that with the increase of essential oil concentration: 1) The final body mass, final body length, weight gain rate and specific growth rate increased first and then decreased, but the feed conversion ratio (FCR) decreased first and then increased. The growth indexes of the low dose group were better than those of the other groups (P<0.05). 2) The activities of pepsin, gastric amylase, intestinal amylase and intestinal lipase in each group increased first and then decreased, and the activities of digestive enzymes increased significantly in the low dose group (P<0.05). 3) The activities of total antioxidant capacity (T-AOC), superoxide dismutase (SOD), catalase (CAT), concentrations of glutathione (GSH) and malondialdehyde (MDA) in the intestine increased first and then decreased, and the difference in the low-dose group was significant (P<0.05). 4) In serum, the concentrations of total protein (TP), globulin (GLOB), total cholesterol (TC), triacylglycerol (TG), low density lipoprotein cholesterol (LDL-CH) and high-density lipoprotein cholesterol (HDL-CH), as well as activities of alanine aminotransferase (ALP) and alanine aminotransferase (ALT) decreased first and then increased. The concentrations of TP, GLOB, TC, LDL-CH and HDL-CH in the low-dose group decreased significantly (P<0.05). To sum up, adding 2 g·kg⁻¹ A. villosum essential oil into basic diet can improve the digestive capacity, intestinal antioxidant capacity and serum biochemical indexes of juvenile tilapia and promote their growth performance.