The pregnane X receptor （PXR） is a crucial regulator of cytochrome P-450 （CYP450） expression. It is involved in oxidative stress， steroid and bile acid metabolism， inflammatory response， apoptosis， cell proliferation and other biological behaviors， and also participates in the metabolism， transport and clearance of chemotherapy drugs. After activation， PXR can affect chemotherapy drug resistance of breast cancer through genetic variation and epigenetic modification， regulation of apoptosis， and participation in phosphorylation/dephosphorylation. It may be a potential therapeutic target for patients with breast cancer resistance.