Abstract: Bacillus amyloliquefaciens JK-JS3, isolated from the leaf of the Pinus massoniana in Mount Zijin, has high nematicidal activity to Bursaphelenchus xylophilus. In order to isolate and purify the nematicidal components, the elementary characteristics of the nematicidal crude toxin have been studied in our experiment. The results indicated that the nematicidal toxin is not a protein which can be evaporated with the water and its maximum optical absorption is from 190 to 220 nm. The nematicidal activity of the toxin can sustain for a long period at 25℃ and 4℃. High temperature and pH condition can affect its nematicidal activity. It has strong nematicidal activity at the alkalinity condition. The nematicidal components can not be dissolved in the organic solvents such as petroleum ether, chloroform and ethyl acetate.