Tissue cutting operations are involved in most surgery. Many human organs such as the kidney, heart and liver are deformable soft tissues. Even in musculoskeletal surgery, cutting on skins or muscles is also operated before a surgeon operates on a joint or a bone. In this research, we take cutter position angle as the core, avoid displaying cutter and nodical calculating miscellaneously, in order to reach the purpose to calculate immediately. In the display of our operation simulation,the deformation and cutting of soft tissue, can reach instant vision of purpose. A complicated anaplastic surgery illustrates the practicality and versatility of the proposed method.