The main purpose of this study is to observe and analyze the characteristics and the clinical significance of long-term echocardiogram data in patients after mechanical aortic valve replacement operation. Fifty-five cases were recruited over 5 years after mechanical aortic valve replacement operation, with complete echocardiogram examination profiles. The 55 subjects were divided into predominate aortic stenosis group and predominate aortic regurgitation group, based on preoperative examinations. And another way of division was also carried out that according to the effective orifice area index (EOAI), the subjects were divided into three groups, i.e., severe prosthesis-patient mismatch (PPM) group, moderate PPM group, and non PPM group. Characteristics of long-term echocardiogram data of the subjects were analyzed. Patients with aortic stenosis showed significantly decreased thickness of intraventricular septum and left ventricular posterior wall about half a year after operation (P<0.05). Half a year after operation, patients with aortic regurgitation showed decreased left ventricular internal dimension diastole and left ventricular internal dimension systole, and increased ejection fraction (P<0.05). Differences in mean aortic valve pressure gradient, forward blood flow across the aortic valves, and ejection fraction were not significant among those with severe PPM, moderate PPM, and non PPM groups (P>0.05). Number of cases of ascending aorta dimension increased as time goes on and pathogenesis of other valve diseases. A conclusion could be drawn that the heart function of patients with aortic valve disease could be improved after mechanical aortic valve replacement operation, but pathologies in other valves and ascending aorta might be increased, and therefore periodical postoperative echocardiogram evaluation with long tem pharmaceutical therapy could be necessary.