Abstract: AIM:To assess the value of intravascular ultrasound (IVUS) in moderate or severe calcified coronary artery disease (CAD) and the prognosis. METHODS: Analysis was made in 219 patients with moderate or severe calcified CAD who underwent percutaneous coronary intervention (PCI) from January 2009 to January 2013. Of the 219 patients, 95 patients underwent PCI under the guidance of IVUS and 124 patients under the guidance of conventional coronary angiography (CAG). RESULTS: No statistical difference was observed between groups in clinical baseline characteristics (including target vessel location, lesion type, number of implanted stents, length, diameter, coronary atherectomy and cutting balloon applications) and in clinical endpoints during hospitalization and 30 days after PCI (including MACE events and the incidence of stent thrombosis). The 1-year follow-up found that the MACE event rate and the target vessel revascularization in IVUS group were significantly lower than those in CAG group (8.4% vs. 17.7%; 3.2% vs. 10.5%; both P<0.05). No significant difference was seen in the incidence of stent thrombosis between groups. CONCLUSION: Although IVUS guidance produces no better immediate postoperative and short-term clinical effect in moderate or severe calcified CHD than that of CAG, the application of IVUS guidance can significantly reduce the postoperative 1-year incidence of target vessel revascularization.