The carotid artery is one of the most easily involved large vessels in atherosclerotic lesions. Its superficial location, good exposure, and low ultrasound interference, coupled with the application of high-frequency body surface probes, make it easier to obtain high-quality images. With the development of imaging technology, the detection rate of carotid atherosclerotic plaque by ultrasound examination is getting higher and higher. The atherosclerotic plaque is dislodged to form an embolus, causing embolic mechanism of distal small artery embolism, which is increasingly recognized. It has become a convenient, economical, safe and reproducible detection method, which not only provides reliable information for the treatment and prognosis of patients with cerebral infarction, but also has important clinical significance for the effective prevention and treatment of asymptomatic patients with carotid atherosclerotic plaque formation.