This study aimed to compare the postoperative function of patients with critical coronary artery lesions undergoing intervention guided by intravascular ultrasound (IVUS) vs those guided by fractional flow reserve (FFR). A total of 226 patients (293 lesions) with coronary angiography-confirmed stenosis of 40% to 70% were enrolled and divided into 3 groups: the IVUS-guided group (98 lesions), the FFR-guided group (101 lesions), and the medical treatment group (94 lesions). In the IVUS-guided group, coronary stent implantation was performed if the minimum lumen area at the stenosis was < 4 mm(2). In the FFR-guided group, intervention was performed if FFR < 0.8. Patients were followed for 1-year postoperatively, and the incidence of major adverse cardiovascular events (MACE), including death, myocardial infarction, and target vessel revascularization, was compared among the 3 groups. There were no significant differences in the degree of stenosis or lesion length among the 3 groups as determined by coronary angiography. The proportion of patients undergoing coronary intervention was significantly higher in the IVUS-guided group compared to the FFR-guided group (P < .001). However, there was no significant difference in the incidence of MACE among the 3 groups (P = .182). This study found no significant difference in MACE between the 3 guidance strategies - IVUS, FFR, and angiography - in patients with intermediate coronary lesions undergoing PCI. These findings suggest that, in this patient population, the choice of guidance method may not impact MACE outcome.