Aim To analyze the expression of calcium activated potassium channel (BKCa), phosphorylated extracellular signal regulated kinase 1/2 (p-ERK1/2) and apoptosis in vascular smooth muscle cells (VSMC) from rabbits with atherosclerosis before and after atorvastatin treatment, and to discuss whether atorvastatin-induced VSMC apoptosis in rabbits with atherosclerosis is associated with BKCa upregulation and ERK signaling pathway inhibition. Methods Experimental rabbits were divided into normal group, atherosclerosis group and atorvastatin group. Tissue samples were taken and rabbit atherosclerotic lesions were observed by HE staining, TUNEL assay was used to measure the apoptosis of VSMC, qPCR and Western blot were performed for detection of rabbit aortic BKCa KCNMB1 mRNA and p-ERK1/2 protein, respectively. Results In atherosclerosis group, the intima of thoracic aorta was significantly thickened, showing typical atherosclerotic lesions. The apoptotic index of VSMC in atorvastatin group was significantly higher than that in normal group and atherosclerosis group (36.51%±1.53% vs. 6.80%±1.08% and 27.83%±1.36%, P＜0.01). The KCNMB1 mRNA expression in atherosclerosis group was significantly lower than that in normal group (105.12±5.50 vs. 147.33±5.76, P＜0.01), while the KCNMB1 mRNA expression in atorvastatin group was significantly higher than that in atherosclerosis group (116.43±6.92 vs. 105.12±5.50, P＜0.01). Phosphorylation of ERK1/2 in atorvastatin group was lower than that in atherosclerosis group (0.90±0.14 vs. 3.48±0.91, P＜0.01). Conclusion Atorvastatin can induce VSMC apoptosis, which may be related to the upregulation of KCNMB1 gene expression and the inhibition of phosphorylation of ERK signaling pathway.