The aim of this experiment was to investigate the effects of raffinose on growth performance and biochemical indices in serum of grass carp. Two hundred and eighty-eight grass carp with average body weight of (69.51±6.29) g were randomly allocated into 6 groups with 3 replicates of 16 fish. The control group was fed with the basal diet, while trial groups were fed with the experimental diets which contained 200, 400, 800, 1 200 and 2 000 mg/kg raffinose, respectively. The experiment lasted for 70 days. The results showed that, compared with the control group, 1) specific growth rate and feed conversion ratio were improved by adding different levels of raffinose, and the group of 1 200 mg/kg was significantly increased (P<0.05); 2) protein deposition rate was improved by adding different levels of raffinose, but the differences were not significant (P>0.05); the fat deposition rate was also increased significantly (P<0.05), except the group of 400 mg/kg; the protein deposition rate and fat deposition rate of the group of 1 200 mg/kg were the highest; 3) triglyceride was significantly improved (P<0.05), and high-density lipoprotein, low-density lipoprotein were decreased significantly (P<0.05). In conclusion: 1) raffinose could improve the growth performance by promoting absorption and utilization of grass carp and promote the absorption of the fat through economizing the protein; 2) raffinose could play a significant role in grass carp by regulating lipid metabolism.