Abstract: In order to explore the effect of fermented soybean meal and soybean meal replacing part of fish meal on the growth performance, hematology, liver antioxidant activities and immune related gene mRNA expression of juvenile coho salmon (Oncorhynchus kisutch), four kinds of iso-nitrogen and iso-lipid and iso-energy feeds were set up in this experiment (crude protein is about 42% and crude lipid is about 15%). The control group was fed with 41% fish meal (FM; fish meal protein accounts for 27%); the experimental groups were replacement of partial fish meal by soybean meal in the FM diets (SM; soybean meal protein accounts for 10% and fish meal protein accounts for 17%), replacement of partial fish meal by soybean meal and fermented soybean meal in the FM diets (SM; soybean meal protein accounts for 5%, fermented soybean meal protein accounts for 5% and fish meal protein accounts for 17%) and replacement of partial fish meal by fermented soybean meal in the FM diets (FSM; fermented soybean meal protein accounts for 10% and fish meal protein accounts for 17%). Those feeds used to feed juvenile coho salmon with an initial weight of (102.25±0.24) g for 10-weeks and the results indicated that there were no significant differences in the weight gain rate (WGR), specific growth rate (SGR), daily growth rate (DGR) and condition factor (CF) between the FSM10 and FM diets (P>0.05), the WGR, SGR and DGR of the FSM5 diets were significantly lower than that of the FM control groups but significantly higher than that of the SM diets (P<0.05) and there were no significant differences in hepatosomatic index (HSI), viscerosomatic index (VSI) and survival rate among groups (P>0.05). There was no significant difference in moisture, crude ash, crude protein among groups (P>0.05), but the crude fat of the SM diets was significantly lower than that of the FM control groups (P<0.05). There were no significant differences in the glucose (GLU), total cholesterol (T-CHO), albumin (ALB) and total protein (TP) between the FSM10 and FM diets (P>0.05) and there were no significant differences in alkaline phosphatase (AKP), aspartate aminotransferase (GOT) and alanine aminotransferase (GPT) among groups (P>0.05), but the GLU, ALB, TP of the FSM5 diets were significantly lower than the FM control diets but higher than the SM diets. The activities of superoxide dismutase (SOD) and catalasehe (CAT) of the FSM10 diets were significantly higher than that of the FM control groups (P<0.05) and there was no significant difference in glutathione (G-SH) between the FSM10 and FM diets (P>0.05). The malondialdehyde (MDA) of the FSM10 diets were significantly lower than that of the FM control groups (P<0.05). The CAT and G-SH of FSM5 of diets wew higher than the SM diets but the MDA wew lower than it. The SOD of FSM5 were lower than FSM10 but have not significant differences with the FM control diets. The relative mRNA expression of gene sod-3, lyz, tlr-3 and c3α of the FSM10 diets were significantly higher than that of the FM control groups (P<0.05), and there were no significant differences in the relative mRNA expression of gene tlr-7 between the FSM10 and FM diets (P>0.05). There were no significant differences in the relative mRNA expression of gene il-6 and hsp-70 among groups (P>0.05). The relative mRNA expression of gene lyz and tlr-3 of FSM5 diets were higher than SM diets. Overall, under the experimental conditions, using fermented soybean meal replace 10% fish meal protein had no significant differences on growth performance and hematology of juvenile coho salmon, but had positive effect on liver antioxidant capacity and immune related gene mRNA expression. Therefore, fermented soybean meal could be used instead of 10% fish meal protein in juvenile coho salmon diets.