Abstract: A 50-day feeding trial was conducted to investigate the effects of dietary chitosan supplement on growth performance and immunity of juvenile Russian sturgeon (initial body weight of 12 g). In total, 540 fish were assigned to six groups (30 fish per replicate, triplicate experiments). The fish were fed basal experimental diets supplemented with different levels of chitosan:0 (control group), 1.25, 2.5, 5, 7.5 and 10 g/kg respectively. The results showed that the weight growth rate (WGR) and specific growth rate (SGR) in 2.5 and 5 g/kg groups were significantly higher than that in control group (P < 0.05), whereas feed coefficient (FC) decreased significantly (P < 0.05), but the growth in 10 g/kg group was inhibited. The superoxide dismutase (SOD) activity in 1.25 and 2.5 g/kg were significantly higher than that in control group (P < 0.05), while the SOD activity in the other three groups were significantly lower than that in control group (P < 0.05). Lysozyme (LZM) activity in serum of 2.5 and 5 g/kg groups increased significantly (P < 0.05), while 7.5 and 10 g/kg groups were significantly lower than that in control group (P < 0.05). The alkanlin phoshpatase (AKP) activity, acid phosphatase (ACP) activity and content of complement C3 in 1.25, 2.5, 5 g/kg groups were significantly higher than those in control group (P < 0.05). No significant difference was observed on serum IgM in all supplementation group (P>0.05). These results indicated that dietary chitosan supplementation can improve the growth performance and immunity in juvenile Russian sturgeon. Based on the WGR, SGR and non-specific immunity, the chitosan supplement in diets was suggested to be 2.5 g/kg for juvenile Russian sturgeon.