Objective：To study the differential proteomics in exosomes of peritoneal dialysis effluent(PDE)from patients with different dialysis ages. Methods：Ten stable peritoneal dialysis(PD)patients were selected and divided into newly enrolled patients group(NEPs group，n=5)and maintenance peritoneal dialysis patients group(MPDs group，n=5)according to the dialysis age. PDE was collected from patients left overnight. Exosomes were extracted by ultracentrifugation and identified by transmission electron microscopy(TEM)，nanoparticle tracking analysis(NTA)，and Western blotting. Label ⁃free quantitative proteomics technology was used to identify and screen the exosomes. Functional enrichment and signal pathway bioinformatics analysis were performed for significantly differential proteins in the exosomes. Results：The exosomes in PDE showed saucer ⁃like vesicles under TEM，and the diameters were between 30 and 150 nm measured by NTA. The specific markers of exosomes，CD63 and TSG101 were detected by Western blotting. A total of 499 proteins were detected by proteomics analysis. After significant difference screening，17 were up ⁃ regulated and 15 were down ⁃ regulated. Gene ontology(GO)analysis showed that these differentially expressed proteins were mainly distributed in chloride channel complexes，cell surface and nuclear matrix，playing a role mainly in binding and catalytic activities，and were involved in biological processes such as positive regulation of binding，oxidative stress response and peroxidase response. Kyoto Encyclopedia of Genes and Genomes(KEGG)pathways were mainly enriched in immunE-related signaling pathways，including IL⁃17signaling pathway and Th17 cell differentiation signaling pathway，which play a key role in peritoneal injury. Conclusion：The differentially expressed proteins screened by label ⁃ free quantitative proteomics technology could be used as candidate markers of peritoneal injury in PD patients and provids molecular clues for revealing the peritoneal fibrosis mechanism of pathogenesis.