Abstract: This paper studied the effects of different dietary amylum content on growth and protease activity of Eriocheir sinensis larvae. Experimental diets were prepared with casein, gelatin, dextrin, fish oil, vitamin mixtures and mineral mixtures, dried at 60℃, then crushed to yield fine particles, and coated with 400 mL cyclohexane which had been saturated with 415g cholesterol.The amlymum content of diets(A1-A6) was 6%-26%, which sieved for the desired particle sizes(160μm, 120μm, 100μm,60μm, and 40μm for Z1, Z2, Z3, Z4, Z5 and M stages respectively). The results showed that that if Eriocheir sinensis larvae were fed diets of different amylum content, their survival, metamorphic rate and weight gain all changed significantly(P3metamorphosed to Z4. During the 20h post metamorphosis of every stage of Eriocheir sinensis larvae, the amylase activity increased at Z1, Z2, Z3 and Z4, and declined at Z5 and M, meanwhile the amylase activity was influenced significantly by the amylum content in diets(P1, Z2, Z3, Z4, Z5 and M were, respectively, 18%, 22%, 18%, 18%-22%, 18%, 14%-18%.