Abstract: An experiment was conducted to study of fatty liver disease resulted from difference lipid levels in juvenile Sciaenops ocellatus diets. 1260 Juvenile Sciaenops ocellatus (initial body weight ca. 2. 73g) were divided into 9 experimental triplicate groups and fed in aquatic cases by a recirculated filtered rearing systemmaintained for 8 weeks at 23. 22. 0. Nine kinds ofdiets were contained withdifferent protein levels (38%, 42%, 46%) and lipid levels (4%, 8%, 12%). The results showed that the relative growth ratio (RGR) and survival ratio (SR) in fish fed medium lipid diets (8%) or higher lipid diets (12%)were significantly lower than fish fed low lipid diets (4%) (P<0. 05), and the contents of lipid in hepatopancreas of fish were positive relatively with the lipid contents of diets. At end of the experimental period, fatty liver disease were found in fish by all nine experimental groups and a large of fishes fed medium lipid diets (8%) and high lipid diets(12%) occurred in serious il- lness and death from 3rd test week, then the top mortality was showed in 5th test week. The ill fishes were sick of eating and movie, black skin, thin and died at last. The main pathological change in ill fishes was fat liver disease. The hepatopancreas were swollen, pale, fatty degeneration and fatty necrosis of hepatocytes and pancreas atrophy. Ultrastural changes showed that there were a lot of fat granules in mitochondria, endoplasmicreticulum and cell plasm on hepatocyte. The research result indicated that all nine kinds of diets with different lipid or protein levels could cause nutritional fatty liver disease in juvenile Sciaenops ocellatus. The degree of pathological changes and serious level of fatty liver disease in test fishes had a close, positive relationship with the contents of the lipid in test diets, but not with the contents of protein in test diets. The raising level of lipid in test diets was sure to the direct cause of illness or death in juvenile Sciaenops ocellatus.