Abstract: In order to intuitively analyze the deformation of the left ventricle （LV） during systole,a mechanical modality analysis method of the LV is proposed in this paper.First,by applying the data of the tagged cardiac magnetic resonance （MR） images,we build a physics-based deformable model with parameter functions of the LV,and then based on the model built we apply the boundary data sets of each frame during systole to reconstruct the3D shape of the LV.Second,we compute the external forces of the LV model during systole by using the tagged data sets of the adjacent two frames.Lastly,the external forces of the model will be transformed to the contractive stress component,the tangent stress component and the vertical stress component.Moreover,these three stress components will be depicted in color cloud pictures.So,the mechanical modality analysis method of the LV proposed in this paper will intuitively and effectively reflect the stress distribution and deformation trends of the inner and outer surfaces of the LV during systole.The acquired cloud pictures of the mechanical modality variation will become an important basis in the medical diagnosis.