In the present study, dietary kaempferol improved the growth, promoted lipid metabolism by decreasing intraperitoneal fat ratio,TG and CHO contents in serum and liver, and enhanced flesh quality by increasing flesh free amino acids contents and the activies of SOD, CAT, GPx and decreasing MDA content in flesh of juvenile grass carp. These improvements might be associated with IGF-1/mTOR, PPAR and Nrf2 pathways. The recommended supplementation level of kaempferol in the diet of juvenile grass carp was 0.8 g/kg.