In this paper, the authors discuss the algorithms for fast-cutting on 3D surface model. Using a 3D reconstruction algorithm based on MC(marching cubes) method, information about grouping and hierarchical bounding boxes are extracted in the generation of 3D surface model. With a B+ tree data structure recording all information, cutting on 3D surface model can be accomplished without tracking all triangular patches. The key point of the algorithms lies in sufficiently employing the information according bounding boxes and 3D (three-dimensional) coherence inherent in MC. It provides a way to fast locate the intersection points and accomplish dividing. The result of this paper can be applied to simulate cutting operation using plane and sphere knife in coxae orthopedics.