Aim To explore the clinical value of prospective ECG-gating low-dose coronary angiography (CCTA) based on iterative reconstruction algorithm (IRA) in the evaluation of mural coronary artery lumen. Methods From January 2015 to January 8,0 patients with myocardial bridge (MB) of left anterior descending coronary artery diagnosed by CCTA and treated in Panzhihua Central Hospital were selected as research objects. Invasive coronary angiography was as the gold standard. According to the degree of MB lesion, the patients were divided into three groups:non-systolic compression group (32 cases), mild systolic compression group (56 cases) and severe systolic compression group (72 cases). The mural coronary artery-contrast opacification difference (MCA-COD), transluminal attenuation gradient (TAG), standardized TAG and MB length were measured and compared in the three groups. The clinical value of standardized TAG, MCA-COD and MB length in the diagnosis of systolic compression MB was evaluated by receiver operating characteristic curve (ROC). Results With the increase of the degree of systolic compression, the TAG and standardized TAG decreased gradually, and the MCA-COD and MB length increased gradually; The difference between the severe systolic compression group and the mild systolic compression group, the non-systolic compression group was statistically significant (P＜0.001). MCA-COD had higher diagnostic sensitivity and specificity than standardized TAG and MB length in detecting whether MB was accompanied with systolic compression, and the combined detection of the three had higher diagnostic value in predicting severe systolic compression. In the mild systolic compression group, the sensitivity of the combined detection was 83.12%, the specificity was 80.00%, and the area under ROC curve was 0.816 (95%CI 0.768~0.864); In the severe systolic compression group, the sensitivity of the combined detection was 90.62%, the specificity was 87.50%, and the area under ROC curve was 0.844 (95%CI 0.799~0.890). The combined detection of the three was more valuable than the single detection of each index. Conclusion MCA-COD, standardized TAG and MB length as prospective ECG-gating low-dose CCTA indexes based on IRA have important diagnostic value for evaluating MB with systolic compression.