To simulate the deformation for soft objects, proposes a local deforming method based on surface area-preservation. The cylinder mesh is employed as the basis mesh to bypass its build step and to uniform the deformation algorithm. The damping curve is employed to simulate the gofferes appearing in the inside section of surface. The gofferes can improve greatly the deformation results. Surface area-preservation and detail-preservation are achieved to improve the authenticity of deformation. The method has been proved feasible and valid to simulate the bending deformation for soft object by experiments results.