Abstract: We studied the responses of 5 immuno-enzymes acid phosphatase (ACP), alkaline phosphatase (AKP), phenoloxidase (PO), peroxidase (POD), superoxide dismutase (SOD) activities in serum of Penaeus monodon (with 1105 copiesg-1 WSSV) to the injection with crude WSSV solution containing 3103 copiesmL-1, 6102 copiesmL-1 and 2102 copiesmL-1 virus and PBS at 15th minute, 30th minute, 1th hour, 3th hour, 6th hour, 12th hour, 24th hour, 48th hour, 72th hour. The activities of ACP, AKP and SOD first increased then decreased and then increased in the 3 groups of WSSV infection, while SOD activity was higher than the initial level significantly; the activities of PO and POD first decreased then increased then decreased and finally increased in the 3 groups of WSSV infection; the PO activity in later and earlier periods were equally the same, but POD activity was higher than the initial level significantly. The reactions of immuno-enzymes are related with the infection concentrations of WSSV, and the most sensitive changes of 4 enzymes activities except acid phosphatase are in the 6102 copiesmL-1 WSSV group. The range of variation in the PBS group is smaller than that of3 groups of WSSV infection.