Objective To investigate the clinical application value of double low coronary CT angiography (CCTA) in the follow-up after percutaneous coronary intervention (PCI). Methods 128 patients (143 measurable stents) with coronary heart disease who underwent PCI were selected as the research subjects. All the patients were given cinventional coronary arteriography (CAG) examination. According to the random number table method, the objects were divided into A, B of two groups with 64 cases in each group. Group A received double low CCTA examination (100kv voltage and 270mgI/mL iodinated contrast agent) while group B received routine CCTA examination (120kv voltage and 350mgI/mL iodinated contrast agent). The results were recorded in detail. CAG was taken as the golden standard to evaluate the specificity, sensitivity and accuracy differences of the double low CCTA in the examination of in-stent restenosis (ISR). The differences in subjective score of image quality, the radiation dose (ED) and the dosage of iodide between double low CCTA and routine CCTA were recorded. Results ①Among the 72 measurable stents in group A, there were 9 stents (12.5%) with ISR and 63 stents (87.5%) without diagnosed by CAG. 8 stents with ISR and 57 cases without were correctly diagnosed by double low CCTA. The accuracy, specificity and sensitivity in the diagnosis of ISR were 90.3% (65/72), 90.5% (57/63) and 88.9% (8/9), respectively. ②The comparison of subjective score of image quality between double low CCTA and routine CCTA was not statistically significant (P>0.05). ED and dosage of iodide in double low CCTA were significantly lower than routine CCTA and the differences were statistically significant (P<0.05). Conclusion Double low CCTA can be used as preferred examination scheme for follow-up and subsequent visit of patients after PCI. The accuracy in the diagnosis of ISR is higher, with clear image, low intake of iodine and low radiation dose, etc. which is worthy of clinical promotion.