Objective：This study was to assess the value of optical coherence tomography（OCT）in guiding the intervention for acute coronary syndrome（ACS）verified by the non-invasive quantitative flow ratio（QFR），functionally. Methods：Patients who were intended to undergo percutaneous coronary intervention（PCI）and evaluated by OCT during operation were enrolled. Patients target lesions with a minimum luminal area（MLA）>2.6 mm2 by OCT and in whom OCT showed no features of plaque rupture or dissection received optimal medical therapy（OMT） and these patients were assigned to OCT-OMT group. The other patients received PCI treatment and were assigned to OCT-PCI group. Data measured by OCT between groups were compared. Functional indexes derived from lesions with high quality images were retrospectively analyzed and validated by QFR. Adverse clinical events between two groups at 1 year follow-up were collected and data statistical analyses were carried out subsequently. Results：A total of 120 ACS patients who were intended to undergo PCI and evaluated by OCT during operation with 146 lesions were enrolled. Forty-seven patients（39.2%）were assigned to the OCT-OMT group，and the other 73 patients（60.8%）were assigned to the OCT-PCI group. According to OCT analyses，the average MLA of OCT-OMT lesions was significantly higher than that of OCT-PCI lesions（3.74 mm2 vs. 2.41 mm2，P < 0.000 1），with area stenosis significantly lower（62.57% vs. 73.58%，P < 0.000 1）. According to QFR analyses，the average QFR value of OCT-OMT lesions was significantly higher than that of OCT-PCI lesions（0.89 vs. 0.75，P < 0.000 1），the “QFR≤0.80” rate of OCT-OMT lesions was significantly lower than that of OCT-PCI lesions（7.14% vs. 84.7% P < 0.000 1）. According to 1 year follow-up，the incidence of major adverse cardiac events（death，myocardial infarction，target vessel revascularization and rehospitalization for angina）and major bleeding events were low（7.5% and 0.8%）with no significant difference between two groups. However，the incidence of minor bleeding events in OCT-OMT group was significantly lower than OCT-PCI group（RR=0.12，P=0.04）. Conclusion：OCT is safe and efficient in guiding OMT for patients with ACS with the standard of MLA>2.6 mm2 and existing neither plaque rupture nor dissection assessed by OCT. QFR can supply functional evidence additionally. Modest consistency was observed in evaluating and guiding for ACS between QFR and OCT.