ObjectiveTo investigate the effect of astragaloside Ⅳ（AS-Ⅳ） on the proliferation of vascular smooth muscle cells（VSMCs） induced by angiotensin Ⅱ（Ang Ⅱ） based on solute carrier family 7 member 11/glutathione peroxidase 4（SLC7A11/GPX4） pathway. MethodsPrimary rat thoracic aortic VSMCs were cultured by tissue explant method， and the cell types were identified by immunofluorescence. Cell counting kit-8（CCK-8） was used to determine the optimal concentration and time of AS-Ⅳ after Ang Ⅱ stimulation. The experiment was divided into blank group， model group， AS-Ⅳ group（40 μmol·L^-1）， Erastin group（0.5 μmol·L^-1）， Erastin+AS-Ⅳ group（0.5 μmol·L^-1+40 μmol·L^-1）. The blank group was cultured in normal medium， the model group was cultured in medium containing Ang Ⅱ（0.1 μmol·L^-1）， and each administration group was cultured in medium containing Ang Ⅱ（0.1 μmol·L^-1） and the corresponding doses of drug. CCK-8 and plate clone formation assay were used to detect the proliferation of cells in each group， Prussian blue staining was used to detect cell iron deposition， the content of reactive oxygen species（ROS） in cells was detected by fluorescence probe method， the content of malondialdehyde（MDA） was detected by thiobarbituric acid（TBA） method， and the protein levels of SLC7A11 and GPX4 in each group were detected by Western blot. ResultsPrimary rat thoracic aortic VSMCs were successfully cultured by tissue explant method， and immunofluorescence detection showed that positive expression of α-smooth muscle actin（α-SMA） and negative expression of vimentin in the cells， identifying them as VSMCs. The optimal concentration and time of AS-Ⅳ determined by CCK-8 were 40 μmol·L^-1 and 24 h， respectively. Pharmacodynamic studies showed that compared with the blank group， the cell proliferation in the model group increased， the iron deposition in the cells increased， the contents of ROS and MDA increased， and the expression levels of SLC7A11 and GPX4 proteins decreased（P<0.05， P<0.01）. Compared with the model group， the cell proliferation of the AS-Ⅳ group was inhibited， the iron deposition in the cells was decreased， the contents of ROS and MDA were decreased， and the expression levels of SLC7A11 and GPX4 proteins were increased（P<0.05， P<0.01）. While in the Erastin group， the cell proliferation was increased， the iron deposition was increased， ROS and MDA contents were increased， and the expression levels of SLC7A11 and GPX4 proteins were decreased（P<0.05， P<0.01）. Compared with the AS-Ⅳ group， Erastin+AS-Ⅳ group showed increased cell proliferation， increased iron deposition in cells， increased ROS and MDA contents， and decreased expression of SLC7A11 and GPX4 proteins（P<0.05）. Compared with the Erastin group， the cell proliferation in Erastin+AS-Ⅳ group was inhibited， the iron deposition was decreased， the contents of ROS and MDA were decreased， and the expression levels of SLC7A11 and GPX4 proteins were increased（P<0.05， P<0.01）. ConclusionAS-Ⅳ can inhibit ferroptosis by regulating the SLC7A11/GPX4 pathway， so as to weaken the proliferation of VSMCs， thus playing a role in the treatment of atherosclerosis.