Objective To evaluate the BiPlane for the quantification of mitral valve area(MVA) in patients with mitral stenosis(MS).Methods Thirty patients with MS were investigated in this study.MVA was calculated by BiPlane in operative.Results MVA in patients with MS measured by BiPlane correlated well with MVA by the(r=0.954),).MVA by BiPlane was slightly greater than the measurement within intraoperative(1.23 cm2 vs 1.20 cm2).Conclusions The BiPlane can easily and accurately acquire the optimal plane of smallest MVA.