With the development of coronary intervention (PCI), a more comprehensive understanding of the anatomical structure and pathophysiological conditions within the coronary arteries is needed to guide interventional treatment. Intravascular ultrasound (IVUS) imaging of coronary arteries in cross-section can not only observe the wall structure and lumen morphology, but also accurately measure the vessel diameter, lumen area and plaque area, clarify the nature and eccentricity of plaque, clarify the nature, severity and stability of angiographically moderate coronary stenosis lesions, and guide further treatment. Some studies suggest that some of the mild lesions shown by coronary angiography are actually severe lesions requiring stent placement by IVUS, confirming that the application of IVUS shows that coronary angiography underestimates the degree of stenosis and that unstable plaques are missed because the nature of the lesion cannot be distinguished by angiography. IVUS can accurately determine the extent and scope of preoperative intravascular lesions, provide an accurate reference for selecting the appropriate stent before stent placement, and enable the operator to better select the diameter and length of the stent to better match the stent and the vessel. After stent placement, the stent size, position, shape, degree of wall apposition, symmetry and deployment satisfaction can be systematically evaluated to ensure that the stent is adequate and not overextended. Coronary angiography can only evaluate the effect of stent placement based on the degree of contrast filling in the vessel lumen, and sometimes the contrast can penetrate into the space between the outside of the stent and the vessel wall, often overestimating the effect of stent placement. Some studies have confirmed that 88% of stents with satisfactory coronary angiographic evaluation of stent placement still have incomplete deployment and poor wall apposition when evaluated with IVUS, requiring an increase in balloon diameter or greater dilation pressure. The study with IVUS confirmed the limitations of coronary angiography in the evaluation of stent placement, which are related to the illusion of satisfactory angiography due to the mesh-like structure of the stent and the residual gap between the stent and the intima. Also, IVUS can illustrate the effect of the nature of the plaque on the stent placement effect, with soft plaques having greater dilation and hard plaques having more tears than hard plaques. It has been shown that after 1-4 post-dilatations in patients with suboptimal stent expansion, their stent apposition and stent deployment area can achieve better IVUS results, with a decreasing trend in restenosis rate and adverse cardiovascular events. It has been confirmed that the minimum cross-sectional area of the stent placed in the coronary artery is an independent predictor of the occurrence of in-stent restenosis, and that high-pressure dilatation can overcome stent expansion insufficiency, obtain a larger stent area, and reduce the occurrence of cardiovascular events. Therefore, in order to prevent thrombosis and prevent restenosis, ideal stent placement should adequately adhere to the wall and completely cover the lesion and intimal tears. Our hospital purchased the third intravascular ultrasound in our province in March this year, and has done a certain number of cases and accumulated certain experience, which has improved the level of interventional diagnosis and treatment of coronary heart disease in our hospital and marked our hospital’s convergence with the international standard in interventional diagnosis and treatment of coronary heart disease.