J-point elevation refers to the elevation of the J-point on the ECG, which is a sudden turning point at the junction of the QRS wave group and ST segment on the ECG, and it often indicates the end of ventricular depolarization and the beginning of repolarization. For J-point elevation, early repolarization syndrome is common and needs to be differentially diagnosed from patients with acute coronary syndrome. On the electrocardiogram, when the J-point elevation is greater than 0.05-0.1 mV, a J wave will be seen. Cardiac enzyme testing and coronary imaging if necessary are recommended to clarify the diagnosis. For ECG J-point elevation in combination with clinical symptoms, such as chest pain, chest tightness with cold sweats, nausea, vomiting, decreased blood pressure and heart failure, it often indicates very early changes of acute coronary syndrome and requires aggressive coronary reperfusion therapy.