The study aimed to detect the total cholesterol Content of Erythrocyte Membranes (CEM) and plasma Cholesterol Efflux Capacity (CEC), and to analyse its correlations with Acute Coronary Syndrome (ACS), in attempt to explore the possible causes of increasing CEM in patients. One hundred and fortyseven patients with Coronary Heart Disease (CHD) were enrolled, while 53 subjects with normal coronary arteriography served as the control group. CEM, CEC, and conventional blood lipid parameters were detected. CEM in the CHD group (138.63 ± 34.92 μg/mg) was significantly higher than the control group (121.29 ± 24.04 μg/mg) (P<0.001). Further analysis revealed that CEM in ACS patients was significantly higher than that in the SAP (Stable Angina Pectoris) group (P<0.001). CEC in the CHD group (1.53 ± 0.40) was significantly lower than the control group (1.67 ± 0.47) (P=0.029). CEC and CEM showed a significant negative correlation (r=-0.257, P<0.001), suggesting that the reduction of CEC might result in an increase in CEM in ACS patients.