Abstract: In this study, we investigated the changes in genome-wide transcript levels of Streptococcus suis after H₂O₂ treatment by transcriptome sequencing to explore the metabolic pathways and genes associated with the process of oxidative stress response in Streptococcus suis under oxidative stress. The strain DN13 of S. suis type 9 was cultured to the late logarithmic phase and treated with PBS and H₂O₂ for 15 min. The transcriptome sequencing（RNA-seq） of the treated strain DN13 was performed. The differentially expressed genes in the transcripts were analyzed by KEGG and GO, and the results of RNA-seq were verified by RT-qPCR. The RNA-seq results showed that a total of 2 005 genes were detected in DN13, and 749 genes were differentially expressed in the experimental group compared to the control group, accounting for 37.4%. The GO enrichment results showed that differentially expressed genes were significantly enriched in three major categories: molecular function, biological process and cellular component. The KEGG enrichment results showed that the differentially expressed genes were mainly concentrated in the ribosome, ABC transporter, amino sugar and nucleotide sugar metabolism, and galactose metabolism metabolic pathways. The RT-qPCR results were consistent with the RNA-seq data, which proved that the RNA-seq analysis results were reliable. This suggests that the response of Streptococcus suis to oxidative stress is a complex process involving multiple bacterial pathways and a series of changes in gene expression. Analysis of gene expression levels of DN13 strains between the experimental group and control group revealed that the expression changes of differentially expressed genes associated with antioxidant in this study were all consistent with their functions and were all annotated to the three GO entries of cataly-tic activity, cellular anatomical entity and binding, suggesting that the data from transcriptome analysis can accurately reflect the changes in expression levels of genes involved in resistance to oxidative stress as a whole.