ObjectiveTo investigate the surgical diagnosis and treatment of chronic stenosis of mechanical prosthetic valve complicated with acute dysfunction, so as to deepen our knowledge on chronic stenosis of mechanical prosthetic valve. MethodsThe clinical data of 5 patients with chronic stenosis of mechanical prosthetic valve complicated with acute dysfunction were retrospectively analyzed, and the relevant literatures were reviewed. ResultsRe-operation (mechanical prosthetic valve replacement) was performed once the diagnoses were confirmed. The patients recovered well; the cardiac function was obviously improved; and there were no early complications. ConclusionChronic stenosis of mechanical prosthetic valve should be strongly suspected when they have symptoms indicating valvular stenosis. Complication of acute mechanical prosthetic valve dysfunction is not difficult to diagnose, and prompt operation is important to save the life of patients.