Non-obstructive coronary heart disease refers to patients with angina pectoris without significant narrowing of the epicardial vessels. Coronary microvascular disease(CMD) is a kind of non-obstructive coronary heart disease, and its clinical detection rate is increasing, seriously affecting the quality of life of patients, and increasing the risk of cardiovascular adverse events, but its mechanism has not been fully understood. This study will prospectively collect patients who meet the diagnosis of CMD, observe the development and outcome of the disease, and explore its occurrence and development mechanism.