The antibacterial activity of 24 kinds of drug towards prawn vibriosis caused vibrio(Z8809) was studied. The minimal inhibition concentration (MIC) and the minimal bacteriocide concentration (MBC) of some drugs against the disease，the effective time of the drugs towards the strain in seawater，and the effect of germ concentration on the value o1 MIC were reported in this paper. The consequences resulting from incorret use of drug were discussed. Emphases were put on the importance and urgency of practising the technique of ecological control in preventing and curing microbial disease of Penaeus.