Aim To explore the effects of intermittent alkaline stimulation on vascular ring calcification from the thoracic aorta of rats induced by high phosphorus and the possible mechanism. Methods Aortic rings were isolated from rat thoracic aorta and cultured in vitro, and randomly divided into three groups:control group, high phosphorus group (containing 10 mmol/L β-glycerol phosphate medium) and intermittent alkaline stimulation group (adjusting pH to 7.7 on the basis of high phosphorus medium). After 14 days of intervention, the expressions of L-type calcium channels (LTCC) β₃ subunit, runt-related transcription factor 2 (Runx2) and smooth muscle protein 22α (SM22α) were detected by immunohistochemical method. The degree of vascular ring calcification was detected by silver nitrate staining and calcium content test. Results Compared with control group, calcium content, the expressions of Runx2 and LTCCβ₃ were significantly increased in high phosphorus group (P＜0.001). Compared with high phosphorus group, calcium content, the expressions of Runx2 and LTCCβ₃ were significantly increased in intermittent alkaline stimulation group (P＜0.001). At the same time, the number of brown and black calcified nodules in high phosphorus group was higher than that in control group, and the number of brown and black calcified nodules in intermittent alkaline stimulation group was higher than that in high phosphorus group. Compared with control group, the expression of SM22α was significantly decreased in high phosphorus group (P＜0.001). Compared with high phosphorus group, the expression of SM22α was significantly decreased in intermittent alkaline stimulation group (P＜0.001). Correlation analysis showed that the expression of LTCCβ₃ was positively correlated with Runx2 protein expression (r＝0.704, P＝0.002) and negatively correlated with SM22α protein expression (r＝－0.670, P＝0.006). Conclusion Intermittent alkaline stimulation can promote high phosphorus induced vascular ring calcification from the thoracic aorta of rats. Its mechanism may be upregulation of LTCCβ₃ protein expression, enhancing the transformation of vascular smooth muscle cells into osteogenesis/chondrogenesis phenotype, and then promoting the occurrence of vascular ring calcification.