In order to estimate the dietary copper (Cu) requirement of bluntnose black bream (Megalobrama amblycephala) in juvenile fish stage, 5 semi-purified diets with different Cu supplementation of 0, 5, 10, 15 and 20 mg/kg (measured values of Cu contents in 5 diets were 16.73, 21.11, 25.24, 29.87 and 34.58 mg/kg, respectively) were formulated with CuSO₄·5H₂O as the Cu source. A total of 400 bluntnose black bream with an initial body weight about 50 g were used as experimental animal and randomly divided into 5 groups with 4 replicates per group and 20 bluntnose black bream per replicate. Each group of fish was fed one diet for 43 days which cultured with net-cage in pond. The results showed as follows: with the Cu supplementation increasing, the specific growth rate (SGR) of bluntnose black bream was firstly increased and then decreased, and the SGR in the group with the Cu supplementation of 10 mg/kg was significantly higher than that in the other groups (P<0.05), while the feed conversion ratio (FCR) had an opposite trend. Through regression analysis, when ditary Cu supplementation was 9.94 mg/kg, equivalent to ditary Cu content was 25.45 mg/kg, the bluntnose black bream had the maximum of SGR; when ditary Cu supplementation was 10.16 mg/kg, equivalent to ditary Cu content was 25.65 mg/kg, the bluntnose black bream had the minimum of FCR. The spine length/body length and spine weight/body weight of bluntnose black bream were increased after supplemented Cu in diets, and the spine length/body length in the group with the Cu supplementation of 20 mg/kg and the spine weight/body weight in the groups with the Cu supplementation of 5, 15 and 20 mg/kg were significantly higher than those in the group without Cu supplementation (P<0.05). The visceral index showed a down trend with the Cu supplementation increasing, and the minimum of visceral index was found in the group with the Cu supplementation of 20 mg/kg, which significantly lower than that in the group without Cu supplementation (P<0.05). With the Cu supplementation increasing, the protein deposition rate and fat deposition rate of bluntnose black bream were firstly increased and then decreased, and the fat deposition rate in the group with the Cu supplementation of 10 mg/kg was significantly higher than that in the other groups (P<0.05), while the protein deposition rate in this group was significantly higher than that in the groups with the Cu supplementation of 20 mg/kg and without Cu supplementation. Through regression analysis, when ditary Cu supplementation was 9.62 mg/kg, equivalent to ditary Cu content was 25.17 mg/kg, the bluntnose black bream had the maximum of protein deposition rate; when ditary Cu supplementation was 10.15 mg/kg, equivalent to ditary Cu content was 25.64 mg/kg, the bluntnose black bream had the maximum of fat deposition rate. Then, by a comprehensive consideration of the SGR, FCR, protein deposition rate and fat deposition rate of bluntnose black bream, dietary Cu requirement of bluntnose black bream in juvenile fish stage is 25.17 to 25.65 mg/kg.