OBJECTIVE:To explore the mechanism of hirudin in the treatment of diabetic kidney disease（DKD）. METHOD:Cytoscape software was used to analyze the network between hirudin targets and active components in the treatment of DKD. The biological function and mechanism of effective targets of hirudin for DKD treatment were analyzed by the Database for Annotation, Visualization and Integrated Discovery（DAVID） database. Molecular docking technology was used to simulate the docking of key targets, and the DKD rat model was used to verify the first 4 key targets with high "Hydrogen number" among the top 10 targets verified by molecular docking. RESULTS:Total of 12334 DKD targets were screened in Gene Cards, OMIM and other databases, Hirudin and DKD had 247 common target genes, and the protein interaction network got 2115 edges. The DAVID database was used for the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis, confirming that hirudin in treatment of DKD involves multiple signaling pathways such as the forkhead box O signaling pathway, the phosphatidylinositol 3-kinase-protein kinase B signaling pathway, the vascular endothelial-derived growth factor signaling pathway and other signaling pathways. The top ten key targets of hirudin in treatment of DKD were verified by molecular docking. Animal experiments showed that hirudin could decrease the expression of caspase-3 in renal tissue of DKD rats, and increase the expression of RAC-alpha serine/threonineprotein kinase, Catalase, and Heat shock protein HSP 90-alpha in renal tissue of DKD rats. CONCLUSION:This study preliminarily reveals that hirudin treats DKD through multiple targets and pathways, and molecular docking and animal experiments indicates the feasibility of this study. Hirudin may be directly or indirectly involved in the regulation of cell metabolism, oxidative stress and other mechanisms in the treatment of DKD, which will lay the foundation for future molecular biological experiments of hirudin in the treatment of DKD.