Aim To investigate the correlation between endogenous inhibitor of nitric oxide synthase(NOS)asymmetric dimethylarginine(ADMA)in patients with coronary artery heart disease and severity of coronary atherosclerosis.Methods A total of 75 patients were enrolled and divided into four groups:stable angina pectoris group(SAP,n=15),unstable angina pectoris group(UAP,n=23),acute myocardial infarction group(AMI,n=20)and control group(n=17).Clinical history was collected and total cholesterol(TC),triglyceride(TG),low density lipoprotein cholesterol(LDLC),high density lipoprotein cholesterol(HDLC)and ADMA levels were determined.Coronary artery lesion was evaluated by Gensinis coring system.Relevance of ADMA to age,sex proportion,TC,TG,LDLC,HDLC,and coronary artery Gensinis coring was analyzed.Results Compared with the control group(3.81±0.48 μmol/L),the serum ADMA level of the SAP group(4.82±0.50 μmol/L),UAP group(5.52±0.55 μmol/L)and AMI group(6.03±1.13 μmol/L)increased significantly(P<0.01).The serum ADMA level of the UAP group and AMI group were higher than that of the SAP group(P<0.01).The difference of the serum ADMA level between the UAP group and AMI group wasn't statistically significant(P=0.279).Gensinis coring of the control group was significantly different from the other three groups(P<0.01).Gensinis coring of the SAP group(17.79±1.86)was significantly lower than those of the UAP group(38.05±4.46)and AMI group(40.62±3.80)(P<0.01).There was nosignificant difference of Gensinis coring between the UAP group and AMI group(P>0.05).Significant correlation between ADMA level and TC,LDLC levels,and Gensinis coring were found(P<0.01).There was no significant correlation between ADMA level and age,sex proportion,TG and HDLC levels(P>0.05).Conclusions The serum ADMA is positively correlative to the degree of coronary atherosclerosis and the morbid state of coronary artery heart disease.It is important for the diagnosis therapy and estimation the morbid state of coronary artery heart disease to observe the changes of the serum ADMA level.