Aim To observe the functional changes in vascular endothelium of obstructive sleep apnea syndrome(OSA) animal models and investigate the association between OSA and coronary atherosclerosis. Methods 16 China swine were divided into obstructive sleep apnea(OSA) group and control group.OSA group was treated by injecting polyacrylamide hydrogel.Animals were sacrificed after 12 weeks.The descending anterior branch of coronary were prepared for examination by transmission electron microscopy.The changes in plasma concentrations of endothelin-1(ET-1) and nitric oxide(NO) were tested before making animal models and after 12 weeks. Results(1) There was a significant lower NO level(57.46±4.55 μmol/L vs.29.64±2.48 μmol/L),higher ET-1 level(46.84±5.39 ng/L vs.71.24±6.13 ng/L) and lower ratio of NO/ET-1(1.25±0.17 vs.0.42±0.02) than those before experiment in OSA group.No difference was found in control group(NO level 60.94±3.28 μmol/L vs.57.72±2.82 μmol/L,ET-1 level 49.24±5.13 ng/L vs.50.19±5.71 ng/L,NO/ET-1 1.25±0.13 vs.1.26±0.06).A marked difference(p<0.05) was showed when these values were compared in two groups.(2)Under electron microsocopy,endothelial cell in animals of OSA group became anomaly.Parts of them were degenerated and exfoliated.Basal lamina of endothelium was not in its integrity. Conclusions Experimental obstructive sleep apnea can injure endothelial cell of blood vessel and make them dysfunction,further initiate and accelerate the process of atherogenesis.