To further clarify the role of bacteria in pine wilt disease (PWD),Pinus massoniana was inoculated with Bursaphelenchus xylophilus (CK),and a mixture of B. xylophilus and the endophytic bacterium GD2 (T),respectively. Transcriptome sequencing,Gene Ontology (GO) and KEGG enrichment analysis were performed on the B. xylophilus,and realtime quantitative PCR (RTqPCR) was used to verify the accuracy of the sequencing results. The results showed that 143 differentially expressed genes (DEGs) were detected,among which 63 were upregulated and 80 were downregulated. GO analysis showed that the DEGs were enriched in immune system process,cell membrane,metabolic process,transporter activity and other functions. KEGG pathway was enriched in ECMreceptor interaction,reninangiotensin system,insulin signaling pathway and other pathways. These GO functions and KEGG pathways were involved in immune regulation and reproductive development of the body. Eight genes were randomly selected for RTqPCR verification,and the expression level was consistent with the sequencing results,which proved the accuracy of the sequencing results. The results showed that strain GD2 could affect the occurrence of PWD by improving the immune regulation ability of pine wood nematode.