Objective To investigate the level of blood 1,25(OH)2D3 and vascular calcification in patients with continuous ambulatory peritoneal dialysis (CAPD), and to explore the factors for serum calcium calcification and blood 1,25(OH)2D3 in patients with CAPD. The role of blood 1,25(OH)2D3 in abdominal aortic calcification(AAC) and significance were explored. Methods A total of 84 patients with CAPD for more than 3 months were enrolled, and clinical data were collected. Lateral radiographic calcification was performed and AAC score (AACs) was calculated. Serum 1,25(OH)2D3 concentration was measured by ELISA. Correlation analysis was used to analyze the relationship between 1,25(OH)2D3 and AACs, logistic regression and multiple regression analysis for risk factors of vascular calcification, and receiver operating curve (ROC) evaluation of 1,25(OH)2D3 for the accuracy of AAC.Results Of 84 patients with CAPD, 34 cases(42.5%) had AAC. The serum level of 1,25(OH)2D3 was lower in CAPD patients, which was negatively correlated with AAC. Oral calcitriol increased serum 1,25(OH)2D3 concentration. Logistic regression analysis showed that elderly patients with diabetes, taking calcitriol, high total cholesterol, high P, high blood uric acid, and low 1,25(OH)2D3 were risk factors for vascular calcification (P<0.05). Multiple regression analysis showed that age, serum phosphorus, and 1,25(OH)2D3 were independent factors for AAC progression (P<0.05). 1,25(OH)2D3 ROC curve area (AUC) was 0.652 (95%CI=0.4420.696, P<0.05), suggesting that 1,25(OH)2D3 predicted the accuracy of AAC. When 1,25(OH)2D3 was 250.43 pg/ml as the cutoff point, the sensitivity of AAC was 55.9%, the specificity 66%, and Yoden index 0.219. Conclusion Serum 1,25(OH)2D3 level in CAPD patients is negatively correlated with the degree of AAC. Low serum 1,25(OH)2D3 level was one of the independent risk factors for AAC. Oral calcitriol can improve 1,25(OH)2D3 levels in patients with CAPD, but in can also increases the risk of vascular calcification, and monitoring on the 1,25(OH)2D3 level should be performed to prevent the risk of vascular calcification.