Abstract:Abstract: [Objective] The pine wood nematode(PWN), Bursaphlenchus xylophilus, which collaborates with its associated bacteria to form ecosystem and has interaction among them, is the pathogen of pine wilt disease. This study focused on revealing the bacterial diversity of ecosystem of pine wood nematode and its associated bacteria. [Methods] The metagenome of ecosystem of bacteria associated with the PWN was analyzed by 16S rRNA gene library and 454 sequencing. [Results] The results showed that 25 OTUs(Operational Taxonomic Units) were obtained from the library according to sequences similarity of 97%, which affiliated to Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Bacteroidetes. The dominant bacteria were belonged to Gammaproteobacteria, especially Stenotrophomonas maltophilia in this class dominated the library. In terms of dominant bacteria, the results revealed by metagenome were similar to that of 16S rRNA gene library. [Conclusion] The diversity of bacteria associated with the PWN is high and these bacteria maybe have ecological role to the PWN.