The physical and chemical property of fatty oil from seed kernel and element content in seed shell and kernel meal of Jatropha curcas L. after extracted oil were analyzed, and the insecticidal activity and feeding value of seed kernel meal were studied preliminarily. The fatty oil of seed kernel has physical and chemical properties with water content 0.012%,relative density (20 ℃) 0.911 g·mL^-1,refraction rate (20 ℃) 1.467, saponification value 193.31 and acid value 34.65. Contents of Ca, P, K, Zn and Mn in seed shell meal are 7.0,1.1,11.6,0.055 and 0.021 mg·g-1,and those in seed kernel meal are 8.0,23.2,22.8,0.130 and 0.057 mg·g-1,respectively. The one or two times dilute solutions of methanol extract from seed kernel meal possess stronger insecticidal activity against Gadirtha inexacta Walker, Prodenia litura Fabricius and Plutella xylostella L. ,with an average mortality rate of 92.6%. The mortality rate of Carassius auratus which is fed with pellet fish feed mixed 20% protein power made from seed kernel meal reaches 83.3%,and the mortality rate of C. auratus fed with pellet fish feed mixed 20% protein power made from same meal but after methanol extraction is only 5.0%. It is suggested that the seed kernel meal of J. curcas contains some elements (such as Ca, P and K) and possesses stronger insecticidal activity, and it is worth deeply exploiting and utilizing to make into pellet fish feed after detoxification instead of protein power.