It is investigated that effects of the four microalgae (Chaetoceros calcitrans, Isochrysis galbana, Thalassiosira pseudonana and Thalassiosira weissflogii) and their mixture, which commonly used as S. constricta rearing diets, on the composition of fatty acids and sterols in juvenile S. constricta. The fatty acid and sterol composition of juveniles were analyzed by GC-MS. The results showed that different diets have effect on fatty acid and sterol compositions in juveniles, and 16 fatty acids and 7 sterols have been detected. C16:2 detected in T. weissflogii and its mix. Juveniles fed with I. galbana mix was abundant in the species of fatty acids（13-15） and C28:1(Δ5/24Me) (Brassicasterol). Besides, the PUFA percentage content of Juveniles fed with I. galbana mix was higher than that of others. Above all, we choose I. galbana mix as optimal diet because they made lipids of S. constricta juveniles more nitrification.