Objective To evaluate image quality of 640-slice coronary CT angiography by combined anesthesia in Tibet minipigs. Methods Tibet minipigs underwent 640-slice coronary CT angiography after anesthesia with xylazine hydrochloride and pentobarbital sodium. The effect of anesthesia was observed and the image quality was evaluated.Results The anesthesia maintained in 40 minutes.The heart rate was (66.66±6.62)beat per minutes.The respiratory frequency was (15.62±1.53)beat per minutes.The revived time was 30 -60 minutes. All of images were good enough to be diagnosed.Conclusion Combined anesthesia with xylazine hydrochloride and pentobarbital sodium has excellent anesthetic effect.It is also simple,convenient and safe.Therefore,it is one of ideal anesthetic methods on such study for 640-slice coronary CT angiography in Tibet minipigs.