Objective:To explore the differences in imaging characteristics and risk factors for mortality between the young and middle-aged and elderly patients with aortic dissection.Methods:The data from 1 220 patients with aortic dissection from January 2007 to December 2015 were successively collected. They were divided into young and middle-aged and elderly groups according to their ages. The basic information, computer comography angiography and echocardiogram results, hospital admissions and surgical details were collected and compared between the two groups using single variable regression analysis.Results:The ratio of female patients in the middle-aged and elderly group (>45 years old) was significantly higher than that of the young group (≤45 years old) (24.9% vs 18.7%, P=0.014), the ratio of hypertension patients was also significantly higher than that in the young group (77.5% vs 68.1%, P<0.001). Echocardiographic parameters showed that the prevalences of left ventricular enlargement (39.9% vs 26.9%) and left ventricular dysfunction (22.3% vs 14.1%) in the young group were significantly higher than in the middle-aged and elderly group (all P<0.001). The prevalences of ascending aorta dilation [(43.04±9.12)mm vs (41.69±10.99)mm] and thrombosis (39.1% vs 28.5%) were higher ( P<0.05). Although there was no statistically significant difference in mortality within 60 days after admission between the two groups (12.0% vs 15.1%, P=0.164), univariate regression analysis showed that aortic branch involvement was the main independent risk factor for mortality in young patients. Left ventricular remodeling (left atrial enlargement, ascending aortic dilation, aortic regurgitation) and decreased heart function were the main independent risk factors for death in the elderly patients. Conclusions:The mortality rate of young and middle-aged and elderly patients with aortic dissection are comparable, but the influencing factors are different. Screening out the relevant risk factors that affect the survival rate of the two groups, and conducting targeted prevention and intervention on them areof great significance to improve the survival rate of patients.