Abstract: The bacterium strain JKJS3 isolated from the leaves of Pinus massoniana has been screened for its high nematicidal activity on Bursaphelenchus xylophilus．The nematicidal activities of JKJS3 on 7 plant nematodes isolated from different dead pine trees and its molecular identification have been studied in this paper. The bioassay result obtained from 24 hours treatment of JKJS3 culture filtrate on different nematodes indicated that nematicidal activities not only effected on B.xylophilus, but also on other kinds of nematodes, the mortality of seven kinds of nematodes all attained 100%. The nematicidal activity of the ten times dilution of culture filtrate on B.hofmanni was the highest with mortality of 96.9%, the second was Seinura lii with 73.7%．The mortality of B.xylophilus and B.mucronatus treated with ten times dilution of culture filtrate was 48.7% and 39.0% respectively, however, the mortality of Aphelenchoides macronucleatus, S.wuae and Ektaphelenchidae sp. were rather lower with 1.5%, 1.5% and 0 respectively. The result from 16SrDNA analysis of strain JKJS3 indicated that the strain and Bacillus amyloliquefaciens FZB42 was at the same brand in the phylogenetic tree, their similarity was 99.86%, and it confirmed the former identification by morphological characters and Biolog, which demonstrated the strain JKJS3 belongs to Bacillus amyloliquefaciens.