Abstract: During the period from 1989-1990,blood samples were taken from 115 individuals of two-year old(2-y) silver carp,Hypophthalmichthys molitrix,and 91 individuals of the 2-y bidhead Carp,Aristchthys nobilis. The blood indices,such as the number of red and white blood cells (RBC and WBC),hemoglobin content (Hb),blood specific gravity (BSG),erythrocyte osmotic fragility (Eof),haematocrit (Ht),erythrocyte sedimentation rate (ESR),differential leukocyte count (DIC) and the normal size (long diameter x short diameter) of the blood cells were investigated. RBC. WBC. Ht. Lym and Mon values are significantly greater in the silver carp than those in the bighead carp,but ESR (120 minute) and Neut. values are significantly greater in the bighead carp than those in silver carp. RBC. WBC. Ht and Neut. values are higher in female than those in male of silver cap. The annual changes of the blood indices of both spotes were also examined and little difference was observed in all of the above indices among individuals of the same species,Therefore,the above indices may be used as reference of the normal physilogical indices for the two species of fish.