Fenneropenaeus penicillatus is one of the main aquatic creatures widely disturbed in southern-east coast of Ningbo,China.To understand the cellular and chemical characteristics,the hemocytes and hemolymph of F.penicillatus were isolated and primarily studied using microscope and chemical analysis.The results showed that the density of hemocyte was(0.43±0.11)×10⁷/ml.A total of three types of hemocytes were isolated including agranuler hemocyte(AH):length 9.7±1.4 μm,width 5.8±0.8 μm,occupying 16.2%±1.8% of the total hemocytes;large-granule hemocyte(LGH):length 11.3±1.3 μm,width 6.7±1.7 μm,occupying 46.6%±3.2% of the total hemocytes;small-granule hemocyte(SGH):length 7.1±0.4 μm,width 5.4±0.4 μm,occupying 35.7%±4.5% of the total hemocytes.Under the condition of 16-18℃ and 60 min incubation time,the phagocytic rate of hemocytes on Staphylococcus aureus(10⁶-10⁷/ml)was 67%±5%.The protein content of hemolymph of the shrimp was 11.78 mg/ml,the relative hemolysis activity of the hemolymph to 3% cock red cells was 2.6,and the coagulant value of the hemolymph to 5% cock red cells was 15-18.The hemolymph showed obvious antimicrobial activity by measuring the area of inhibition of growth around the disc with 10±1 mm to Staphylococcus aureus and 6±2 mm to Escherichia coli.The work laid a foundation to the further research of the active peptides.