Objective To investigate the feasibility and effect of stentedpulmonary autograft replacement and find out the best way to treat mitral valve diseases. Methods From August 2006 to October 2007, 20 male sheep at the age of about 1 year old underwent mitral valves replacement operation in Anzhen Hospital. Weight of these sheep was 50.0±6.0 kg. They were randomly divided into two groups. Ten sheep in the experimental group underwent RossⅡsurgery in which we first sutured pulmonary valve onto a pulmonary valve stent, transferred the valve to the mitral valve annulus and then reestablished the outflow tract of the right ventricle. The other 10 sheep in the control group underwent bioprosthetic valve replacement routinely. Ultrasonic cardiogram (UCG) was employed 6 hour after operation to measure the effective orifice area (EOA) of the mitral valve, mitral peak velocity of early filling, the peak pressure gradient (PPG), the extent of regurgitation, left ventricular enddiastolic dimension (LVEDD) and ejection fraction (EF). Results One sheep in the experimental group died of low cardiac output syndrome; one in the control group died of unmanageable bleeding during operation, and the others all survived. Six hours after operation, UCG of the experimental group showed that the heart valves were well fixed, valve echo was clear, and there was no perivalvular leakage or mitral valve stricture or regurgitation, but moderate pulmonary valve regurgitation occurred in 1 case and mild in 2. There was no significant difference between the two groups in PPG (11.86±1.28 mm Hg vs. 10.98±0.98 mm Hg,t= 1.670,P=0.110) and the mitral peak velocity of early filling (1.72±0.09 m/s vs. 1.65±0.07 m/s, t=1.680,P=0.110). However, EOA of the experimental group was smaller than the control group (2.23±0.09 cm2 vs. 2.39±0.08 cm2, t= 4.240,P= 0.001). Conclusion The experimental result of sheep mitral valves replacement with stentedpulmonary autograft is satisfying. The new mitral valves work well and the surgery method is feasible.