Abstract: With the viscosity solution of Eikonal equation,a method is proposed on the 3D reconstruction of convex surface based on an image.Then,the additive saddle surface and multiplicative saddle surface are defined.By utilizing the methods of convexity reconstruction and concave reconstruction,two parabolic cylinders may be reconstructed based on one saddle image,and according to the characteristics of saddle surface, a complete saddle surface could be composed by the two parabolic cylinders.The algorithms possess the feature of high accuracy and no edge restriction is imposed since the computation starts from the critical point.In the paper,the sensitivity of algorithms to noise is also analyzed through experiments.