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 1×10⁵ copies·g^-1 WSSV) to the injection with crude WSSV solution containing 3×10³ copies·mL^-1, 6×10² copies·mL^-1 and 2×10² copies·mL^-1 virus and PBS at 15^th minute, 30^th minute, 1^th hour, 3^th hour, 6^th hour, 12^th hour, 24^th hour, 48^th hour, 72^th 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 6×10² copies·mL^-1 WSSV group. The range of variation in the PBS group is smaller than that of 3 groups of WSSV infection.