Abstract: 【Objective】To conduct transcriptome sequencing analysis on Sesuvium portulacastrum under salt tolerance,and to find out genes related to salt tolerance in the root of S. portulacastrum,so as to provide reference for studying molecular mechanism of S. portulacastrum.【Method】 Illumina sequencing technology was applied to compare and analyze the transcriptomesand the differentially expressed genes(DEGs)related to salt tolerance inroots of S. portulacastrum under 0 mmol/L NaCl(control group)and 400 mmol/L NaCl salt stress(salt stress treatment group), respectively. Thirteen DEGs were selected to verify the reliability of transcriptome data by using quantitative real-time PCR(qRT-PCR) analysis.【Result】A total of 305145 transcripts with an average length of 622 bp were identified in the roots of S. portulacastrum transcriptome. In the control group,146177 transcripts were greater than 300 bp;in the salt treatment group, 72173 transcripts were greater than 300 bp. A total of 65535 unigenes were successfully annotated in the five databases of Nr,GO,Swiss-Prot,COG and KEGG,accounting for 52.36% of the total unigenes and including 182 heat shock protein genes. A number of 24042 DEGs between the control group and the salt stress treatment group were identified. Thirteen candidate genes were selected for qRT-PCR analysis,and the result showed that 9 genes were up-regulated and 4 genes were down-regulated,which was consistent with transcriptome sequencing analysis. Among the 24042 DEGs, 10106 significant DEGs were enriched in 129 metabolic pathways. The top 10 enriched metabolic pathways were ribosome,biosynthesis of secondary metabolites,RNA transport,endocytosis,spliceosome,glycerophospholipid metabolism,protein processing in endoplasmic reticulum,phagocytosis,ether lipid metabolism and plant-pathogen interaction path. Differential genes in sulfur metabolism,proline accumulation,eactive oxygen species (ROS)metabolism,calcium signaling pathway and hydrogen peroxide metabolism related to salt stress were up-regulated.【Conclusion】 Under salt stress, DEGs in S. portulacastrum,such as small molecular heat shock protein genes,genes related to anti-oxidation and genes related to ion exchange,play an important role in regulation.