One of the most important complications of diabetes is cardiovascular system pathology, which has become a serious threat to the health and workforce of diabetic patients and is a major cause of death. Diabetic heart disease mainly includes: diabetic cardiac microangiopathy, macroangiopathy, cardiomyopathy and cardiac autonomic dysfunction. From the current epidemiological survey, coronary heart disease is the most common complication of diabetes mellitus. According to the World Health Organization, the prevalence of coronary heart disease in diabetic patients is 26%-35%. From the viewpoint of pathological changes, the pathological changes of coronary heart disease complicated by diabetes are basically the same as those of non-diabetic patients with coronary heart disease, but the number of branches involving coronary artery lesions is larger, the degree of stenosis is also heavier, and myocardial infarction is prone to occur; from the viewpoint of clinical manifestations, the clinical manifestations of coronary heart disease complicated by diabetes are similar to those of coronary heart patients without diabetes in general, and angina pectoris, acute myocardial infarction, heart failure and arrhythmia can occur, but there are The incidence of diabetic coronary artery disease increases with age and disease duration, but is not related to the severity of the disease, and decreases with the degree of control of diabetes, and the incidence of painless myocardial infarction increases, which may be related to autonomic neuropathy caused by diabetes; the incidence and mortality rate of myocardial infarction is higher, and patients with diabetic myocardial infarction suffer from complications such as cardiac arrest, shock and heart failure This may be related to the autonomic imbalance and reduced cardiac stability that comes with diabetic neuropathy. Diabetic cardiomyopathy is a heart disease caused by diabetic myocardial microangiopathy. Due to myocardial microvascular wall thickening and lumen narrowing, myocardium can have extensive ischemia, degeneration, necrosis and fibrosis. Myocardial metabolism is disturbed and cardiac function is diminished. The symptoms of cardiac insufficiency may appear early, especially in female patients with hypertension, and the heart may have mild enlargement, panic and shortness of breath, and angina pectoris. In severe cases, acute heart failure, shock, arrhythmia and even sudden death may occur. Clinically, it is often not easy to distinguish coronary heart disease. Diabetic patients often have cardiac phytonadic dysfunction, which is characterized by reduced heart rate variability, manifested as increased heart rate at rest, little change in activity, the difference in heart rate during deep breathing is also reduced, the acceleration reflex of the heart rate is weakened when rising quickly from the prone position, fast and fixed tachycardia is often the main manifestation of diabetic cardiac autonomic neuropathy. About 40-60% of long-term diabetic patients have reduced heart rate variability. In diabetic patients who die of acute myocardial infarction, autopsy may reveal a decrease in the number of cardiac autonomic fibers and often segmental pyknotic or orbicular thickening changes that predispose them to sudden death due to severe arrhythmias. Therefore, examining the heart rate variability of patients is helpful to judge their cardiac autonomic function, and can be used to guide treatment to prevent the occurrence of serious arrhythmias, and can also be used as a reference indicator for judging the condition. Due to the increasing trend of the prevalence of diabetes in China in recent years, it has caused a significant increase in the above-mentioned heart disease complications. Therefore, clinicians should pay attention to patients with type 2 diabetes mellitus who are old, have a long disease duration, and have cardiovascular risk factors, including independent risk factors for insulin resistance, even if they do not have relevant cardiovascular symptoms in clinical practice. Patients should undergo necessary noninvasive cardiac function tests, such as echocardiography and heart rate variability, and be closely monitored for changes in their condition. Once diagnosed, patients should be treated actively, including general treatment, diet control, use of insulin, rapid control of hyperglycemia, use of B-blockers in patients with myocardial infarction, and thrombolytic therapy if necessary; in cases of heart failure, routine cardiac diuresis and vasodilation, but thiazide diuretics should be avoided to prevent aggravation of glucose metabolism disorders.