Abstract: A 90-day feeding trial was conducted to determine the effects of vitamin C on the non-specific immunity, three HSPs mRNA expression and disease resistance of juvenile Wuchang bream (Megalobrama amblycephala) initial mean body weight of (6.400.05) g. The fish was selected and randomly divided into six groups and Vc supplemented at 0.2, 33.4, 65.8, 133.7, 251.5 and 501.5 mg/kg diet, respectively. The fish was fed for 90 day. Compared with the control, the contents of serum C3 of the 501.5 mg/kg Vc group were increased, the contents of serum C4 of the 133.7 mg/kg Vc group were improved; the hepatic SOD activities of 65.8251.5 mg/kg Vc groups were enhanced and the hepatic ASAFR activities of all treated groups were enhanced; the expression level of HSP60 mRNA of 133.7 and 251.5 mg/kg Vc groups were improved, the expression levels of HSP70 and HSP90 mNA of 251.5 mg/kg Vc group were significantly improved (P0.05); the survival rates in all treated groups were significantly higher than that of the control at 12 h and 24 h after injecting Aeromonas hydrophila (P0.05), and the survival rate of the 251.5 mg/kg Vc group was the highest. Other indices, such as total protein, albumin, serum cortisol and MDA were not significantly different from the control (P0.05). Therefore, the basal diet supplemented with 133.7251.5 mg/kg doses of Vc could improve the immunity of juvenile Wuchang bream effectively.