For coronary artery diseases, imaging diagnosis is usually used to guide the treatment. However, it can only reflect the geometric characteristics of the disease but does not determine the hemodynamically significant stenosis. This study was aimed to investigate the relationship between angiographic and functional severity of coronary artery stenosis and to improve the diagnostic value of imaging. 39 patients with 55 stenosis vessels were included in this study. The correlation between FFR and stenosis rate was analyzed with the medical statistical analysis method, and the influence of the position of stenosis and coronary dominant type on the correlation was discussed. By regression analysis, the stenosis rate of left anterior descending artery of right dominant type showed a significant correlation with FFR value (r≈0.79, P < 0.000 1) after grouping with position and the dominant type. Due to the significance of a value of the FFR < 0.80 in determining inducible ischemia, the diagnostic accuracy of myocardial ischemia by the stenosis rate increased from 70.9% to 82.8% after grouping. Sensitivity (from 72.2% to 78.6%) and specificity (from 70.3% to 86.7%) were also significantly improved. This study indicates that the position of stenosis and the coronary dominant type are significant influence factors on the correlation between FFR and stenosis rate. Consideration of these two factors in the diagnosis of myocardial ischemia by imaging will be helpful to improve the effectiveness of diagnosis.