Aim To explore the relationship of serum level of eosinophilic cation protein(ECP)and classification of coronary artery lesions through measuring their levels.Methods The study enrolls 70 patients with coronary heart disease(CHD),and 30 patients without CHD as controls.All patients were confirmed by angiography.According to the number of diseased vessels,we divided the patients into three groups: 1-vessel disease group,2-vessel disease group and 3-vessel disease group;and then analyzed the relationship between the level of ECP and the number of diseased vessels respectively.Results The serum levels of ECP in CHD group were higher than those in control group(P<0.01).The relationship between the serum levels of ECP and the number of diseased vessels were statistically related among three groups(P<0.01).Multiple linear regression analysis showed that levels of ECP were closely associated with the severity of coronary artery lesions.In multivariate analysis,ECP levels were significantly associated with CHD independent of traditional risk factors.Conclusions The study indicates that the higher serum levels of ECP may be related to the initiation and development of coronary artery lesions.So the higher serum levels of ECP is likely one of the indexes to predict the severity of the coronary artery lesions.