The experiment was conducted to study the activities of fatty acid synthase,acetyl-CoA carboxylase and arnitine palmitoyltransferases and effects of glucose and vitamin c on them during yolk-sac larva development of Carassius auratus.The characteristics of fatty acid synthase,acetyl-CoA carboxylase and arnitine palmitoyltransferases activities during yolk-sac larva development of C. auratus were analyzed by the method of enzymology. The results showed that:In the group of control and vitamin c,the acitvity of atty acid synthase and acetyl-CoA carboxylase were increasing, and arnitine palmitoyltransferases activities were showed wave-like carves down-up during yolk-sac larva development of C. auratus.while the acitvity of three kinds of enzymes were increasing in the group of glucose,and they significantly higher than that of control group during yolk-sac larva development(P<0.05). In the vitamin c group, the activity of acetyl-CoA carboxylase was significantly higher than that of control group in endogenous nutrient stage, the activity of fatty acid synthase was significantly higher than that of control group between mixed nutrient stage and exogenous nutrient stage, the activity of arnitine palmitoyltransferases was significantly higher than that of control group in endogenous nutrient stage and exogenous nutrient stage,respectively.The research showed that: Fatty acid synthase,acetyl-CoA carboxylase and arnitine palmitoyltransferases play an important role in maintaining the dynamic balance of lipid metabolism during yolk-sac larva development of Carassius auratus.Glucose solution(15g/L) could regulate lipid metabolism enzyme activity form new levels of lipid metabolism to meet the needs of growth and development, and vitamin c solution( 30mg/L) has play an important role in maintaining the normal lipid metabolism. during the development of larva.