Cutting is one of simulations to the real actions in virtual surgery system, reality and real-time performances are the key factors for modeling cutting. Therefore, it is necessary to study new soft-tissue cutting algorithm，which belongs to element subdivision algorithm. The algorithm is different from other element subdivision algorithms. It divides the whole subdivision process into two smaller processes: firstly the incomplete-cutting element is decomposed into complete-cutting element, then the basis element decomposition is performed according to different cutting cases. Experiment results show that using this new algorithm for tetrahedron, finite element model can provide well visual result.