Control effect of an avirulent bacterlocin-producing strain(ABPS) Y6l-1 of Pseudomonas solanacearum on bacterial wilt was 58.8 % when the bacterial suspension had poured onto the rhizosphere soil of tobacco cultivar NC82 on one day before transplanting to the field and of hilling time. Until eight weeks after inoculation, survival of the strain on rhizoplane and in stem of the plants inoculated was better than that of other four strains tested. It suggested that survival of the ABPS in and on the plants should be supported for the sufficient protection.