Rheumatic fever is a non-suppurative disease of connective tissue in pediatric period, often involving blood vessels, skin, plasma membranes, brain, heart and joints, etc., especially after inducing myocarditis, which can leave permanent valve lesions, clinically prone to recurrent attacks, which is extremely harmful to pediatric patients, and we must pay sufficient attention to it. At present, the etiology and mechanism of rheumatic fever are not well understood. Most experts believe that the sick child has a history of pharyngitis, tonsillitis, upper respiratory tract infection and other group A group B hemolytic streptococcal infections within 1-4 weeks before the disease. The infected bacteria do not directly invade the connective tissue of the body, but are caused by the body’s autoimmune response. The initial manifestation is often irregular fever, pallor, mental discomfort, abdominal pain, excessive sweating, followed by wandering large joint swelling and pain, limited movement, and red rash at the trunk and extremities, irregular ring-shaped, higher than the skin, called ring-shaped erythema. Subcutaneous nodules may appear on the extensor surfaces of the elbow, wrist, knee and ankle joints. In girls with the disease, there are mostly involuntary, involuntary and irregular movements. In severe cases, the heart is often invaded and endocarditis, epicarditis and myocarditis occur. Rheumatic damage to the heart can be cured if treated promptly. In contrast, heart involvement, such as frequent recurrence of rheumatic activity, is prone to develop into chronic rheumatic valve disease. The main lesion of rheumatic fever invasion of the heart is the involvement of heart valves, mitral valve, aortic valve damage is common, the acute phase of valve hyperplasia swelling, endothelial cell membrane damage, rough surface, collagen fibers exposed, platelets, fibrin can form gray-white corn-like flab, endocarditis. When the inflammation subsides or recurs, the valve becomes stiff and thickened due to massive fibrous tissue proliferation and contraction, producing adhesions and shortening, leading to valve stenosis and incomplete closure. When myocarditis occurs, rheumatic vesicles are formed in the interstitial small vessels of the myocardium, and scar formation occurs in the late stages, often leading to life-threatening cardiac insufficiency. In a few children, chest pain and pericardial grinding sounds may occur, which often suggest that the child is infected with rheumatic pericarditis, but it is less common. Therefore, once a child is found to have the above-mentioned manifestations, the diagnosis of rheumatic fever can be confirmed by examining the increased blood sedimentation and the increase of anti-“O”. During the active period of rheumatic fever, the child should be allowed to rest in bed, given easily digestible protein and vitamin food, and use enough penicillin continuously for 10-14 days, take anti-rheumatic drugs on time, and use cardiac stimulants and other comprehensive treatment early when it is accompanied by heart failure. If the child returns to normal, continue to observe the changes in the child’s condition. In case of clinical re-occurrence of tonsillitis, pharyngitis and other infections, antibiotics, hormones or anti-rheumatic drugs should be used quickly to prevent recurrence and rebound of the disease and further involvement of the heart.