ObjectiveThis retrospective study aimed to investigate the correlation between the cardiopulmonary exercise test (CPET) and the severity of coronary stenosis (SYNTAX score) in patients with stable coronary artery disease (SCAD), thereby assessing CPET's diagnostic value.MethodsWe classified 220 patients who underwent coronary angiography into coronary heart disease (CHD) and non-CHD groups based on stenosis severity. Patients with SCAD were categorized into mild, moderate, and severe groups by the SYNTAX score. CPET was performed, and data on the general information, serological indicators, and echocardiographic parameters were collected. CPET parameters included oxygen uptake related to the work rate (△VO