Lysobacter antibioticus strain 064 is a potential biocontrol agent against soft rot disease of Amorphophallus konjac root caused by Pectobacterium carotovora subsp. carotovora (Pcc). Biocontrol mechanism of Lysobacter antibioticus strain 064 against Pcc was observed based on antagonism, colonization and nutrition competition. The results indicated that strain 064 showed antibacterial activity against Pcc strains with different virulence. It could colonize on the root and the rhizosphere of A.konjac and the organism could maintain 32 d with 102104cfu/g. Nutritional requirement experiments showed that the similarity of sole-carbon-source utilization between Pcc and strain 064 was 46.88 %, suggesting a nutritional competition between the two microorganisms. Strain 064 also significantly reduced the bacterial soft rot index of A. konjac by 58.92 % in field plot in 2007.