Objective To summarize the short and mid-term outcome of adult patient suffered with aortic stenosis and small aortic root treated by aortic root enlargement with supraannular prostheses replacement or supraannular prostheses replace-ment.Methods From January 2005 to January 2017, 223 patients with aortic stenosis and small aortic root who underwent i-solated aortic valve replacement(AVR) were included in this retrospective study cohort.Patients with aortic insufficiency who underwent isolated AVR or those who underwent combined valve replacement were excluded from the study cohort .Aortic root enlargement with supraannular prostheses replacement was performed in 98 patients(ARE), and supraannular prostheses re-placement was performed in the remaining 125 patients as a control group(SP).The mean age and other baseline characteristics were compared between the two group, except that body surface area(BSA) in ARE were higher than that in SP[(1.62 ± 0.04)m2 vs(1.61 ±0.04)m2, P=0.015].Results Operative mortality occurred in 6 patients(2.7%), the cause of death including low cardiac output syndrome(LCOS, 3 patients), multiple organ failure(MOF, 2 patients) and stroke(1 patient). Reoperation for bleeding occurred in 5 patients and acute renal failure in 9 patients, pneumonia in 5 patients.The other nonfa-tal operative complications included wound complication(8 patients), temporary pacing therapy(24 patients), and new onset of acute mitral regurgitation(1 patient).The operative mortality and nonfatal complication were not statistically different be-tween the two groups.Patients in ARE received more bioprotheses and iEOA was higher than those in SP .Transvalvular pres-sure gradients and incidence of patient-prostheses mismatch were lower in ARE.At the 2 years of follow-up, transvalvular pres-sure gradients and left ventricular mass index were statistically lower in ARE compared with SP .The iEOA of ARE was higher than that in SP(1.22 ±0.13 vs 0.87 ±0.13, P<0.01).However, during the mid-term follow up(mean duration of follow-up was 6.31years), the overall survival rate was not statistically different between the two groups.Conclusion The strategy of aortic root enlargement with supraannular prostheses to treat adult patients with aortic stenosis and small aortic root can provide more optimal hemodynamic effect , effectively avoid PPM and was not associated with increased risk of mortality or adverse event when compared with strategy of supraannular prostheses replacement.However, the mid-term survival rate was not statistically different between the two strategies.