We investigated how conjugated linoleic acids (CLA) can affect the growth, body composition and me-tabolism-related hepatic enzyme activities of juvenile hybrid grouper (♀ ). Fishes with initial body weight of (63.57±0.56) g were examined after 8 weeks of feeding with isonitrogenous and isolipidic diets in which 0 (CLA0), 0.8% (CLA0.8), 1.6% (CLA1.6), 2.4% (CLA2.4) and 3.2% (CLA3.2) of conjugated linoleic acid were supplemented. The results showed that:(1) there were no significant differences in weight gain ratio (WGR), survival rate (SR), specific growth rate (SGR), condition factor (CF), hepatosomatic index (HIS) and viscerosomatic index (VSI). The protein efficiency ratio (PER) increased as levels of dietary CLA rose, and was significantly higher in all experimental groups than in CLA0 groups (<0.05). Feed intake (FI) was reduced with increasing dietary CLA; FI in group CLA0 was significantly higher than that in other groups (<0.05). Feed conversion ratio (FCR) was decreased, and achieved in the group CLA2.4, which was significantly lower than CLA0 (<0.05); (2) muscle fat content increased as amounts of dietary CLA rose, and the achieved in the group CLA0.8, which was significantly lower than that in group CLA0 (>0.05). The content of saturated fatty acid (SFA) and C_18:0 in the muscle of group CLA1.6 was significantly higher than in group CLA0 (<0.05), and monounsaturated fatty acid (MUFA) content in CLA3.2 achieved minimum as well as C_18:1n-9, which was significantly lower than that of control group ( in groups CLA2.4 and CLA3.2 were significantly higher than in the control group (18:1n-7 content were significantly lower than in group CLA0 ( content of muscle and liver in groups CLA2.4 and CLA3.2 were significantly lower than in group CLA0 ( content in muscle and liver were highly related with dietary CLA supplement, and in all experimental groups were significantly higher than in CLA0 groups (<0.05); (3) dietary conjugated linoleic acid levels among glucose-6-phosphatedehydrogenase (G6PD) activity in the experimental groups were significantly higher than those in the control group (<0.05); acyl-coenzyme aoxidase activity has the highest CLA3.2 activity, which was higher than in the other groups (<0.05); general esterase and fatty acids ynthetase activity in the experimental groups was significantly higher than in the control group (<0.05).The results indicate that dietary CLA can significantly improve the utilization of aquafeed by juvenile hybrid grouper, improve the composition of fatty acids in liver and muscle, and increase metabolism-related hepatic enzyme activities.