Objective The aim of this study was to invstigate the level of coronary endothelial injury and dysfunction, the variation of vardiac angiotensin II(Angll), and their correlations in patients with stable angina(SA)or unstable angina(UA).Methods The 20 patients with UA, 17 patients with SA and 18patients excluding coronary heart disease(control)were studied. Blood samples were collected during percutaneous corontary intervention(PCI). We investigated the coronary endothelial injury and dysfunction by measuring the concentrations of nitric oxide(NO), endothelin(ET) and the number of circulating endothelial cells(CEC) in coronary sinus blood. The aorta-coronary sinus gradient was measured as cardiac Angll.The Angll concentration of peripheral blood was also measured. Results In angina patients,especially in UA patients, NO concentration in coronary sinus blood was lower, while ET concentration and CEC number were markedly higher than those in control group(p<0.01,or p<0.05).Angll concentration in angina patients, especially in UA patients was higher than that in control group (p<0.01,or p<0.05). The coronary endothelial injury and dysfunciton showed a positive correlation with cardiac Angll concentration, No obvius correlation was seen between coronary endothelial injury and peripheral Angll concentration. Conclusion In angina patients especially UA patients, the coronary endothelium is injured and the cardiac Angll is activated obviously. The coronary endothelial injury and high expression of vardiac. Angll may affect each othe.This may result in the aggravating lesion of coronary artery.