In order to explore the gene expression of Brassica campestris L.under drought stress,Dengmu rape was used as the test material,normal irrigation at seedling stage as the control,and drought for 8 days as the treatment group.By analyzing the differentially expressed genes under different water conditions in Dengmu rape,we found that there were 3 057 significantly different genes under different water conditions,including 1 616 significantly up-regulated genes and 1 441 significantly down regulated genes.There were 7 172 up-regulated genes and 731 down regulated genes in GO annotation;through the enrichment analysis of KEGG pathway,we found that RNA degradation,eukaryotic ribosome biosynthesis,ribosome,pyrimidine metabolism and purine metabolism were the main pathways involved in the enrichment of up-regulated differential genes under drought stress.The main path-ways involved in the down-regulation of differential gene enrichment under drought stress were valine,leucine and isoleucine degradation,plant hormone signal transduction,photosynthesis,linoleic acid,α-linolenic acid metabolism,etc.;a total of285 555 transformed SNPs and 485 985 transversed SNPs were found.These results indi-cated that there were differences in gene expression of Dengmu rape under drought stress,which enriched the gene information database of Brassica campestris L.and laid a foundation for molecular breeding in later stage.