Aim To investigate the relationship between the severity of coronary lesions and asymmetric dimethylarginine （ADMA） as well as circulating endothelial progenitor cells （EPC） in patients with coronary heart disease （CHD）. Methods 130 cases were divided into two groups: CHD group（n80） and control group （n50）, and CHD patients were divided into three groups according to the result of coronary angiography and the CHD Gensini’s scoring system. The levels of plasma ADMA were measured. Total mononuclear cell were isolated from peripheral blood by Ficoll density gradient centrifugation, and were cultured in medium supplemented with 10% fetal bovine serum, vascular endothelial growth faactor （VEGF） and basic fibroblast growth factor （bFGF）. After 7～10 days cultured, the numbers of colony-forming units （CFU） of EPC were counted by phase-contrast microscope. Results The levels of plasma ADMA were significantly higher in single vessel disease group and multitude vessels disease group than those in control group （P<0.05 and P<0.01）, and in Gensini’s scores ≥60 group, ADMA levels were significantly higher than those in control group （P<0.01）. With the increase of Gensini’s scores and lesion count, plasma ADMA levels increased obviously （P<0.05 and P<0.01）. Meanwhile, the numbers of CFU of circulating EPC were significantly lower in single vessel disease group and multitude vessels disease group than those in control group （P<0.01）, and in Gensini’s scores ≥60 group, Gensini’s scores 31～59 group, Gensini’s scores ≤30 group， the circulating EPC numbers were significantly lower than that of control group （P<0.01）. With the increase of Gensini’s scores and lesion count, EPC numbers decreased obviously（P<0.05 and P<0.01）. The Gensini’s score of coronary lesion and plasma ADMA was positively correlated （r0.365, P0.027）, and negatively correlated with the numbers of circulating EPC （r－0.16, P0.015）. There was a strong negative correlation between the levels of plasma ADMA and the numbers of CFU of circulating EPC （P<0.01）. Conclusions Corresponding with the degree of coronary atherosclerosis severer, the plasma CFU levels were higher in CHD group than those of control group, the numbers of circulating EPC of CHD patients were lower than those of healthy person. ADMA accumulation may contribute to EPC depletion, with consequent impairment of EPC-mediated endothelial repair, which can promote atherogenesis. ADMA was negatively correlated with the number of CFU of circulating EPC. In vivo ADMA can promote endothelial dysfunction by means of depressant EPC proliferation.