Objective To analyze the clinical manifestation and imaging manifestation of moyamoya disease, and to ex-plore the application value of double source FlashCT angiography and its post-processing technique in the diagnosis of moyamoya disease. Methods Clinical characteristics and data of imaging examination of 21 patients with moyamoya disease who were admitted to our hospital from January 2013 to July 2014 were retrospectively analyzed. Results①Age of onset of moyamoya disease was around 17-42 years old, and patients younger than 40 years old accounted for 90% of the total. The clinical manifestation was mainly ischemia, and weakness of limbs and hemiplegia were the most commonly seen. ②CT indicated that 13 patients were cerebral infarction, 6 patients were cerebral bleeding, and 2 pa-tients were cerebral bleeding complicated with cerebral infarction. CT angiography and DSA showed stenosis or block-ing of bilateral or unilateral internal carotid artery, anterior cerebral artery and middle cerebral artery, and showed the formation of abnormal vessel network at the base of the brain like smoke. Conclusion For children and adults who have repeated occurrence of transient ischemic attack, cerebral bleeding, and cerebral infarction, moyamoya disease should be highly suspected. CT angiography can be selected as the first choice of examination, and DSA examination should be performed timely for clinically suspected cases.