Cardiac ultrasound is a non-invasive technique that can detect changes in the structure, function and blood flow of the heart and large blood vessels, and is of great importance in the diagnosis, treatment decision making, efficacy evaluation and prognosis of patients with heart disease. For some patients with obesity, emphysema and thoracic deformity, transesophageal ultrasound can be used if the image quality of transthoracic exploration is not satisfactory and affects the judgment of the condition. With the improvement of people’s material living standard and the growth of aging population, the incidence of hypertension and coronary heart disease is increasing. Therefore, the use of echocardiography for safe and non-invasive examination of the heart is of pivotal importance for the prevention and treatment of diseases. It can evaluate the heart valve function, myocardial hypertrophy, myocardial motion, cardiac systole and diastole in elderly patients for early prevention of heart failure and myocardial infarction. For some patients with congenital heart disease, it can determine what type of congenital heart disease they belong to, so as to determine whether to operate and the surgical plan. For some patients with atrial septal defects and ventricular septal defects undergoing interventional occlusion, cardiac ultrasound can also be used to detect the proper placement of the occluder during the procedure. With the continuous development of echocardiographic technology, the evaluation of cardiac function by echocardiography has expanded from the evaluation of left ventricular function to the function of other chambers such as the right ventricle and atria, from systolic function to diastolic function, from overall function to local function, and from the evaluation of resting state function to the evaluation of myocardial perfusion, functional reserve, coronary reserve, myocardial viability and other functions under load. The evaluation of myocardial perfusion, cardiac reserve, coronary reserve, and myocardial viability in a loading state has evolved. The application of new technologies not only allows the measurement of real-time volume changes in the heart chamber as a whole and in each segment, but also allows the quantitative analysis of myocardial motion, displacement, deformation, and the temporal and sequential phases of motion in all directions, thus providing a fuller understanding of myocardial motion characteristics and biomechanical properties.