Objective:To investigate the diagnostic value of quantitative flow ratio(QFR)combined with coronary stenosis assessed by related optical coherence tomography(OCT)parameters in intermediate coronary lesions. Methods:From October 2016 to February 2020,a total of 89 patients with 109 lesions were enrolled in the First Affiliated Hospital of Nanjing Medical University. All patients underwent coronary angiography suggesting intermediate lesions(stenosis between 50% and 90% by visual estimation)and lesions were evaluated by OCT. Baseline data,quantitative coronary angiography data(QCA)and coronary lesions characteristics were collected and lesions were retrospectively analyzed by QFR. The diagnostic value of QFR in intermediate coronary lesions was evaluated when coronary significant stenosis defined as minimal lumen area(MLA)<2.5 mm2 or area stenosis(AS)≥75% by OCT. Results:Compared with the non-significant stenosis group,QFR in the significant stenosis group was significantly lower(P < 0.001). AS assessed by 2D-QCA was significantly higher than that assessed by OCT(P=0.007)and 3D-QCA(P < 0.001)derived from QFR. AS evaluated by 3D-QCA and OCT had no significant difference(P=0.356). According to linear regression,OCT-MLA was correlated positively with QFR significantly(r=0.56,P < 0.001). OCT-AS was correlated negatively with QFR significantly(r=-0.60,P < 0.001). ROC-analysis revealed that 0.81 is the ideal QFR cut-off to identify coronary lesions with significant stenosis(AUC:0.837,95% CI:0.754~0.901,P<0.001,sensitivity 83.3% and accuracy 80.0%). Conclusion:The application of QFR combined with OCT can accurately predict the coronary stenosis and evaluate the coronary functional parameters,which can guide the diagnosis and treatment in intermediate coronary lesions.