Objective To identify the ECG performance of high-risk patients during the treadmill exercise test.Methods We retrospectively analyzed the result of treadmill exercise test（TET） of 1174 patients had coronary heart disease（CHD） who accepted coronary angiograph in Shanghai First Hospital from 2016 to 2020. According to the result of coronary angiography

all the patients were divided into high-risk CHD group（n=494） and common CHD group（n=680）. Patients in the high-risk group had >70% blocked in at least of one vessel. We compared the types and characteristics of the patients’ electrocardiogram（ECG） during the TET in the two groups. Results The high-risk groups have significantly ECG signs:（1）Newly appear ST segment level or arched elevation

ST segment elevation >0.1 mV in lead a VR;（2）ST segment depression>0.2 mV lasted over 5 minutes in the corresponding leads of each wall of the ventricle

it lasted at least 3 minutes until the recovery phase;（3） Frequent premature ventricular contractions

paroxysmal ventricular tachycardia accompany ST depression;（4） New appeared conduction block and ST segment depression

and ST segment elevation in lead a VR;（5）De winter picture;（6）Chest pain and low blood pressure and ST segment depression. Conclusions Treadmill exercise test（TET） can find high-risk CHD patients

High-risk patients have significant ECG signs.