Abstract: BJLSH9,an actinomycete exhibiting both nematicidal and antifungal activities,was isolated from rhizospheric soil of willows in Beijing.Bioassay results in vivo showed that the efficiency of BJLSH9 suppressing the radial growth in Phytophthora nicotianae was up to 50.05%,and nematicidal activity towards Panagrellus redivivusuat in 48 hours was up to 98.05%.The optimal fermenting time was 72 hours by the measuring the highest mycelial biomass and nematicidal efficiency in a 40 L-fermentor with No.38 medium.The BJLSH9 was identified as Streptomyces flavofungini based on a phylogenetic analysis of the 16S rRNA gene.Tryptophandehydrobutyrine diketopiperazine (TDD),a nematicidal secondary metabolite of BJLSH9,was identified and the nematicidal activity was up to 40% in 48 hours.This was the first report on the nematicidal nature of S.flavofungini and TDD.