Abstract: The variations on innate immune activities of the shrimp (Fenneropenaeus chinensis), which acutely infected by Vibrio harveyi or experienced break out of WSSV, were studied in this paper1 The experimental juvenile shrimp was injected muscularly with V1harveyi solution(712 @ 107CFU/mL) 30LL per shrimp1 The groups uninjected and injected with axenic physiological saline were two controls1 The activit ies of superoxide dismutase (SOD) and lysozyme (LSZ) of dead and alive shrimp within 48h infection were determined1 The survival injected with V1harveyi 48h later displayed a very significant higher SOD act ivity than those of the two controls and the dead1 There was no significant difference of SOD activity among the two controls and the dead caused by V1harveyi infection in 48h1 The LSZ activity of the shrimp infected by V1harveyi was dropped very significantly1 The earlier the shrimp died, the lower the LSZ activity of the shrimp was1 The shrimp in an earth pond was transfered into 3 indoorcement ponds at random1 One as control, and the others were experiments of WSSV break out which induced by enviromental stress1 Compared to the shrimp no WSSV syndrome, the shrimp withWSSV syndrome showed very significant decline in the total haemocyte counts (THCs), SOD activity and LSZ activity, but a very significant increment of protein concentrat ion in haemolymph1 The phenoloxidase (PO) activity of the shrimp withWSSV syndrome was not significantly increased1