Abstract: To investigate the effects of substitution of fish meal by fermented soybean meal on the growth performance and serum biochemistry of Trachinotus ovatus, we have formulated five experimental diets, adding 0% (FM), 25% (FSM25), 50% (FSM50), 75% (FSM75) and 100% (FSM100) fermented soybean meal to replace fish meal. In order to eliminate the effects of limiting amino acids, we added 0%, 0.10%, 0.22%, 0.35% and 0.45% lysine, as well as 0%, 0.14%, 0.27%, 0.41% and 0.54% methionine, respectively. The results show that the weight again rate, specific gain rate, specific growth rate and feed intake did not have significant difference among FSM25, FSM50 and FM groups (P>0.05), but the feed conversion ratio in FSM100 group was significantly higher than that in FM group (P<0.05). There was insignificant difference in the muscle moisture, ash, crude protein, crude fat contents between the fermented soybean meal groups and FM group (P>0.05). The serum aspartate aminotransferase (AST) activities and total protein (TP) contents in FSM75 and FSM100 groups were significantly higher and lower than those in FM group, respectively (P<0.05). The activities of alanine aminotransferase (ALT) and superoxide dismutase (SOD) in FM100 group were significantly higher than those in FM group, respectively (P<0.05). The relative expressions of IGF-1 and GH genes in FSM75 and FSM100 groups were significantly lower than those in FM group (P<0.05). In summary, by adding limiting amino acids, the substitution of fish meal by fermented soybean meal not exceeding 50% does not have adverse affects on T. ovatus. According to the regression curve, the substitution level of 17.5% will achieve the best effects.