〔Abstract〕 Objective To investigate the effect of baicalein on breast cancer cell mcf-7 and xenograft tumor in nude mice and its possible molecular mechanism. Methods CCK-8 was used to detect the effect of different concentrations(0, 20, 50, 100 μmol/L) of baicalein on the proliferation of breast cancer cells; flow cytometry was used to detect the cycle distribution and apoptosis rate of breast cancer cells. Transcriptome sequencing was used to analyze the possible signaling pathways affected by baicalein. Western blot was used to detect the effects of baicalein on related proteins; in addition,in vivoexperiments with nude mice xenograft model were used to explore the effects of baicalein on nude mice Impact. Results Compared with the control group, baicalein could inhibit the proliferation of breast cancer cells in a time-and concentration-dependent manner, induce breast cancer cell cycle arrest, and significantly induce its apoptosis; meanwhile, after baicalein treated mcf-7 cells 48 h, the expression level of PCNA, a marker of proliferation, significantly reduced. The expression level of Cleaved-Caspase3 protein gradually increased, and the expression level of Caspase3 protein gradually reduced. In addition, baicalein could also regulate the PTEN/PI3 K/AKT signaling pathway. The expression level of tumor suppressor protein PTEN gradually increased with concentration increasing, and the expression levels of p-PI3 K and p-AKT protein decreased significantly with concentration increasing; meanwhile,in vivoexperiments showed that baicalein could inhibit mcf-7 xenograft tumor growth. Conclusion Baicalein has an inhibitory effect on the proliferation of breast cancer cell line mcf-7 and induces apoptosis. The mechanism may be related to the regulation of PTEN/PI3 K/AKT signal axis, providing a new antitumor activity for baicalein basis.