Aim To investigate the relationship between concentrations of apolipoprotein M and coronary artery lesions in patients with coronary heart disease(CHD). Methods According to coronary angiography,73 patients with CHD were enrolled as CHD group and 47 non-CHD patients as control group.Enzyme-linked immuosorbent assay(ELISA) was used to measure the serum apolipoprotein M levels.The serum levels of apolipoprotein M in CHD patients were compared with control group;The serum levels of apolipoprotein M were compared in the different quantity and severity of coronary artery lesions. Results The serum concentrations of apolipoprotein M in CHD patients(10.12±1.79 mg/L)were significantly lower than in the controls(11.69 ±2.02 mg/L,P<0.01);The serum levels of apolipoprotein M were lower in multi-vessel coronary artery lesions group(9.19±1.22 mg/L) than in double-vessel(10.36±1.94 mg/L) and single-vessel group(11.22±1.69 mg/L);The serum apolipoprotein M levels of light-stenosis(11.39±1.58 mg/L),moderate-stenosis(10.14±1.46 mg/L),severe-stenosis group(9.04±1.30 mg/L) were decreased gradually;The serum levels of apolipoprotein M negatively correlated with the quantity(r=-0.485) and severity(r=-0.508) of coronary artery lesions(P<0.01). Conclusion Apolipoprotein M appears to play protective roles in prevention of atherosclerosis.