Abstract： Objective To discuss the change and significance of plasma nitric oxide(NO) and endothelin concentrations in coronary heart disease(GHD) with one-vessel stenosis.Methods Plasma levels of NO and endothelin were measured simultaneously in 126 patients,including 62 patients with one-vessel stenosis between 50％ and 70％ (group A)and 32 patients ＞70％ (group B),30 patients without CHD(group C).Results The values of plasma NO were all decreased more significantly in group A and B than those in group C [ (43 ± 12) μmol/L,(50 ± 11 ) μmol/L vs (58 ± 12) μ mol/L,P ＜ 0.01 ] ; furthermore they were markedly decreased in group B than in group A ( P ＜ 0.01 ).The values of plasma endothelin were markedly higher in group A and B than those in group C[ (60 ± 12) pg/L,(80 ± 22)pg/Lvs(50 ± 11 )pg/L,P ＜ 0.01 ]; furthermore they were higher in group B than in group A ( P ＜ 0.01 ).Conclusions Metabolism disorder of NO and endothelin may lead to spasm of coronary artery.The values of plasma NO and endothelin may estimate coronary vessel's stenosis degree.