OBJECTIVE: To explore the mechanism of Buyuan Decoction on small airway dysfunction in chronic obstructive pulmonary disease（COPD） by using network pharmacology and molecular docking methods. METHODS: The active ingredients and drug targets of Buyuan Decoction were screened out through the TCMSP system pharmacological database and analysis platform（TCMSP）. The network diagram of the relationship between the active ingredients and targets of Buyuan Decoction was drawn using Cytoscape 3.9.1

and the targets of COPD were found through the Mendelian genetic comprehensive database and GeneCards database. The common targets of Buyuan Decoction and COPD were screened out through Venny diagram

and the selected intersection targets were introduced into STRING platform for target protein-protein interaction（PPI） analysis

and visualization was realized with the help of Cytascape 3.9.1; The Metascape website is used for gene ontology（GO） bioinformatics analysis and Kyoto Encyclopedia of Genes and Genome（KEGG） pathway enrichment analysis

and Autodock-vina 1.1.2

Mgltools 1.5.7 and Pymol 2.4.0 are used to realize molecular docking. RESULTS: 153 active components

284 targets of action and 1 038 targets of COPD were obtained; There are 49 common targets of Buyuan Decoction and COPD. The enrichment analysis shows that there are 3 879 biological processes

297 cytological components

414 molecular functions

and 214 KEGG pathways. The core components of Buyuan Decoction in treating COPD are kaempferol

quercetin

and sitosterol. PPI results show that the mechanism of Buyuan Decoction in treating COPD is interleukin 6（IL-6）

matrix metalloproteinase 9（MMP9）

tumor necrosis factor（TNF）

and protein kinase B（Akt） 1

vascular endothelial growth factor A（VEGFA） and tumor protein p53（TP53） have significant effects. The key signal pathways are advanced glycation end products（AGE）-AGE receptor（RAGE） and hypoxia inducible factor-1（HIF-1）. CONCLUSIONS: Buyuan Decoction can treat COPD with multiple components

multiple targets and multiple pathways. It acts on targets such as IL-6

TNF

VEGFA

MMP9 and Aktl through active components such as kaempferol

quercetin and sitosterol

and inhibits the release of cytokines through AGE-RAGE signal pathway and HIF-I signal pathway

reduces the excessive immune response of small airways and eliminates inflammation

prevents the destruction of alveolar attachment points around small airways

and promotes angiogenesis

Then improve the small airway function

achieve the effect of treating COPD

and effectively improve the lung function and exercise endurance of COPD patients.