[Research background] This study is conducted to investigate the effects of dietary Silphium perfoliatum L. (SP) supplementation on the growth performance, antioxidant capacity and lipid metabolism of juvenile Megalobrama amblycephala. [Method] Four experimental diets were formulated containing 0% (control group), 2%, 4% and 6% SP. 240 healthy juvenile M. amblycephala (3.85±0.5) were randomly fed one of the four experimental diets in triplicates (20 fish per tank) for 8 weeks. After the 8-week feeding trial, the growth performance, muscle composition, plasma biochemical indicators, hepatic and intestinal antioxidant capability, and the gene expressions relating to lipid metabolism were measured. [Results] The results showed as follows: 1) Compared to the control group, the growth rate (GR) and specific growth rate (SGR) were significantly lower in the 4% and 6% SP groups (P<0.05). The final body weight (FBW) was significantly lower in the 6% group than that of the control group (P<0.05), while the feed coefficient ratio (FCR) was significantly higher (P<0.05). 2) As to the antioxidant capability, the levels of catalase (CAT) and superoxide dismutase (SOD) in the intestine were significantly higher in SP supplementary groups compared to the control group (P<0.05). 3) In terms of fat deposition and lipid metabolism, fat contents in the muscle of the 4% and 6% SP supplementary groups were significantly higher than that in the control group (P<0.05). The intestinal lipase activity was significantly lower in the 4% and 6% SP supplementary groups compared to the control group (P<0.05). The contents of plasma triglycerides (TG), cholesterol (TC), high-density lipoprotein (HDL-C), and low-density lipoprotein (LDL-C) of the 6% SP supplementation group were significantly higher than that of the control group (P<0.05). Thereafter, the gene expressions showed that the gene expressions of hepatic fas and srebp1c, relating to lipid synthesis, were significantly activated in the 4% and 6% SP supplementary groups (P<0.05). The gene expressions of hepatic lpl, cpt1a and pparβ, relating to lipolysis metabolism, were significantly inhibited in the 6% SP supplementary group (P<0.05). 4). At the end of the 8-week feeding trial, a challenge test of intraperitoneal injecting 50% CCl4 solution was performed on fish. It was found that the cumulative mortality rate of the 2% SP supplementary group was lower than that of the control group at 24 h post-injection. Further analysis of hepatic antioxidant capacity at 24 h post-injection revealed that the hepatic SOD activity of the 2% SP supplementary group was significantly higher than that of the control group (P<0.05). [Conclusion] In general, the supplementation of 2% Silphium perfoliatum L. in diet showed no negative effect on the growth and feed utilization of juvenile M. amblycephala, but improved the intestinal antioxidant capacity. 4% and 6% dietary inclusion levels of Silphium perfoliatum L. inhibited the growth and resulted in fat deposition in the muscle. [Meaning] All the results of this study provided a reference for further application of Silphium perfoliatum L. in aquatic feed.