In this study,network pharmacology prediction and in vitro experimental verification were used to explore the common targets and possible mechanisms of daphnetin against malignant glioma,liver cancer and triple-negative breast cancer.The targets of daphnetin and malignant glioma,hepatocellular carcinoma and triple negative breast cancer were retrieved by using Swiss Target Prediction and GeneCards database,respectively.The protein-protein interaction network between daphnetin and three kinds of tumors was constructed by using Cytoscape,and the core targets were screened.GO and KEGG enrichment analysis was performed on the core targets.The molecular docking study of daphnetin with core targets were carried out using the AutoDock Tools.CCK-8 and Western blot were used to verify the effects of daphnetin on the cell inhibition rate and the protein expression levels of p53 and RRM2 in U-251MG,HepG-2 and MDA-MB231 cell lines.56 core targets of daphnetin against three kinds of tumor were screened.Enrichment analysis showed that the core targets were enriched in p53 pathway and cancer pathway and involved in biological processes such as cell cycle regulation,apoptosis,DNA biosynthesis and repair.Molecular docking results showed that daphnetin strongly bound with P53 and RRM2.In vitro results showed that Daphnetin significantly inhibited U-251 MG,HepG-2,MDA-MB231 proliferation (P < 0.01),up-regulated P53 protein expression and down-regulated RRM2 expression in a dose-dependent manner (P < 0.05).Our results suggested that daphnetin can inhibit the proliferation of U-251MG,HepG-2 and MDA-MB231 cells,and its mechanism may be related to the regulation of p53/RRM2 pathway.