Mitral stenosis is the more common type of rheumatic heart valve disease. Patients with this disease usually have typical clinical manifestations such as dyspnea, hemoptysis, cough, hoarseness, and mitral valve facies. However, if there are similar symptoms typical of mitral stenosis, the diagnosis of the disease type can be confirmed by combining the appropriate ancillary tests. 1, echocardiography: the diagnosis of mitral stenosis has a high specificity, in addition to determining the presence or absence of mitral stenosis and orifice area, it can also help to understand the morphology of the heart, determine the degree of valvular disease and determine the mode of surgery, and is also of great value in observing changes before and after surgery and the recurrence of mitral stenosis after surgery. 2.X-ray examination: the x-ray view is related to the degree of mitral stenosis and the stage of development of the disease, mild mitral stenosis, the heart shadow can be normal, moderate stenosis. In the examination, it can be found that the left atrium is enlarged, the pulmonary artery segment is prominent, the left bronchus is elevated, and the right ventricle can be enlarged, etc. The posterior anterior position, the heart shadow is like a pear, which is called “mitral heart”. The pulmonary manifestations of mitral stenosis are mainly pulmonary stasis and marked deepening of the hilar shadow. Due to the redistribution of pulmonary venous blood flow, there is often an increase in vascular shadow in the upper part of the lung and a decrease in the lower part, and the pulmonary lymphatics are dilated. 3, electrocardiogram: mild mitral stenosis, the electrocardiogram can be normal, moderate, severe mitral stenosis, its better early electrocardiogram changes are characteristic of the left atrial enlargement of the P wave, that is, P wave widening and bimodal, called mitral P wave, with the progress of the disease, when the combined pulmonary hypertension involving the right heart, there can be electrical axis right deviation and right ventricular hypertrophy electrocardiogram performance, arrhythmia in patients with mitral stenosis Arrhythmias are very common in patients with mitral stenosis and can be manifested as atrial prophase contractions in the early stage. Cardiac catheterization: In rare cases where the diagnosis is difficult, cardiac catheterization should be considered. The main manifestations of cardiac catheterization are increased pressure in the right ventricle, pulmonary artery and small pulmonary artery, increased resistance to pulmonary circulation, and decreased cardiac output.