The mitral valve is the valve between the left atrium and the left ventricle and is located between the left atrium and the left ventricle, with the projection on the body surface located at the left fourth sternal rib joint. In clinical practice, physicians often use auscultation to initially determine whether a patient has mitral valve disease. The mitral valve auscultation zone does not coincide with the position of the body projection of the valve. The mitral valve auscultation zone is located at the point of strongest apical beat. When the heart is of normal size, the mitral valve auscultation zone is mostly located slightly medial to the left midclavicular line between the 5th ribs. Under normal conditions, the mitral valve is like a one-way door. When the heart contracts, the mitral valve valve opens and blood flows from the left atrium to the left ventricle to ensure blood circulation. When the heart is diastolic, the mitral valve closes and blood does not flow backwards into the left atrium. However, when there is disease of the mitral valve, blood may flow backwards and the patient will have corresponding clinical symptoms and abnormalities during mitral valve auscultation. For example, in common rheumatic heart disease mitral valve closure insufficiency, the auscultation is characterized by blowing wind-like, rough, loud, and high-pitched in nature, mostly occupying the full systolic phase, conduction to the left axilla or left scapula, and obvious during exhalation and left lateral recumbency.