Objective：To prepare a pig model of obstructive sleep apnea-hypopnea syndrome (OSAHS) and to observe the hemodynamics and pathological characteristics of common carotid artery, so as to lay a foundation for further studying the effect of OSAHS on cardiovascular system.Methods: Twelve male small-type pigs were randomly divided into model group and control group (n=6). Animals in the model group were housed in a negative pressure chamber for 6 months to establish OSAHS model and those in the normal control group were fed routinely. After pigs in the model group presented the symptoms of OSAHS, the changes in hemodynamics of carotid artery were detected with color Doppler ultrasound. The morphological changes of common carotid artery were analyzed under light microscope and electron microscope. Results: Animal model of OSAHS was successfully created. The internal diameter of carotid artery of pigs in the model group was decreased, the intima was increased, and the peak-systolic mean velocity (S) and the resistance index (RI) were both increased compared with those of the control group (P<0.05) . The results of light and electron microscope revealed that the elastic plate was incomplete, the media thickness was increased, the morphology of smooth muscle cell became irregular, the collagen fiber bundles were increased, and some elastic fibers and smooth muscle layers were in disorder. Quatitative analysis showed that the elastic fibers in the media of carotid artery increased significantly in the model group(P<0.01).Conclusion: Pathological changes in tissue structure and haemodynamics occur in negative pressure-induced pig OSAHS model. Alterations in upper airway pressure can cause damage to the cardiovascular system.