Aim To study the relationship between coronary atherosclerosis and plasma endothelin. Methods The levels of plasma endothelin of 43 patients with coronary atherosclerotic heart disease(CHD) and 21 normal persons were measured using radioimmunoassay (RIA). The group with multi vessel disease and the group with single vessel disease were divided accoding to the numbers of vessel disease. Results The mean level of plasma endthelin was obviously increased in CHD group than in control group(P<0.01); The mean level of plasma endothelin was markedly increased in the group with multi vessel disease than in the group with single vessel disease (P<0.05); The concentration of plasma endothelin was strongly related to the number of vessel disease (r=0.414; P<0.05). Conclusion The plasma endothelin had correlation with the occurrence or degree of coronary atherosclerosis.