The purpose of this study was to study the effects of equal-sulfur DL-methionine (DL-Met) and methionine hydroxy analogue free acid (MHA-FA) supplementation in diets on growth performance, activities of digestive and absorptive enzymes and antioxidation indices of juvenile Jian carp (Cyprinus carpio var. Jian). A total of 450 fish with average initial weight of (8.24±0.03) g were randomly divided into 2 groups with 3 replicates in each group and 10 fish per replicate. The fish of two groups were fed practical diets supplemented with DL-Met and MHA-FA on equal-sulfur basis, respectively. The trial lasted for 60 days. The results showed as follows: MHA-FA and DL-Met had the same effects on weight gain, feed conversion ratio, productive values of protein, fat and ash in juvenile Jian carp (P>0.05), but the feed intake in MHA-FA group was significantly lower than that in DL-Met group (P<0.05). Glutamate-oxaloacetate transaminase (GOT) and glutamate-pyruvate transaminase (GPT) activities in muscle and hepatopancreas and plasma ammonia content also had no significantly difference between MHA-FA and DL-Met groups (P>0.05). The activities of trypsin and amylase in intestine and hepatopancreas, lipase and amylase in intestine were not significant different between MHA-FA and DL-Met groups (P>0.05), while the activities of lipase and amylase in hepatopancreas in MHA-FA group were significantly lower than those in DL-Met group (P>0.05). The activities of alkaline phosphatase (AKP) in foregut and midgut, Na+,K+-ATPase in foregut, midgut and hindgut, γ-glutamyl transpeptidase (γ-GT) in midgut and creatinekinase (CK) in whole intestine were not significantly different between MHA-FA and DL-Met groups (P>0.05). However, the activities of AKP in hindgut, γ-GT in foregut and hindgut in MHA-FA group were significantly lower than those in DL-Met group (P<0.05). Compared with the DL-Met group, the content of MDA in serum, intestine and hepatopancreas in MHA-FA group was significantly higher (P<0.05), while the activities of glutathione (GSH) in serum, catalase (CAT) in serum and intestine, glutathione S-transferase (GST), glutathione peroxidase (GSH-Px) in intestine and hepatopancreas in MHA-FA group were significantly lower (P<0.05). In conclusion, supplementation of MHA-FA and DL-Met on equal-sulfur basis in juvenile Jian carp diet nearly obtained the same feeding effects.［Chinese Journal of Animal Nutrition, 2010，22（4）:1122-1130］