Aim To explore the value of intravascular ultrasound (IVUS) and quantitative coronary angiography (QCA) in the interventional therapy of borderline coronary lesions. Methods 60 patients with borderline coronary lesions(coronary artery stenosis between 40％～70％ confirmed by coronary angiography (CAG)) were enrolled. They were divided into QCA group(n=30, received QCA examination after CAG) and IVUS group (n=30, received IVUS detection after CAG). QCA and IVUS quantitative analysis were used to measure difference in reference vessel diameter, minimal lumen diameter, minimal lumen area, stenotic rates of diameter and area between two groups, and qualitative analysis was used to detect coronary plaques imaging morphology with IVUS. Finally, all the patients were followed up for 12 months. Incidence rate of major adverse cardiovascular events (MACE) during admission and follow-up were compared between two groups. Results Compared with QCA group, the ratio of lumen diameter stenosis ((57.80％±8.18％) vs (51.73%±7.91%)) and area stenosis ((67.01％±10.41％) vs (57.07%±10.71%)) were increased, while the ratio of minimum lumen area ((3.90±0.79) mm² vs (4.14±0.60) mm²) was decreased in IVUS group (P＜0.05). Meanwhile there was no MACE during admission in two groups, but the incidence rate of MACE was significantly lower in IVUS group than that in QCA group since one month after follow-up started(P＜0.05). Conclusion Compared with QCA, IVUS can detect more severe stenosis rate of angiographical borderline lesions, more effectively detect “unstable” lesions, guide percutaneous coronary intervention of borderline lesion, reduce the occurrence of cardiovascular events, and improve the prognosis.