In order to solve the incompatibility between real-time property and realism, we introduce a method for 3D rock fracturing simulation based on the Havok Physical Engine in this paper. Firstly, during the model preprocessing stage, the seed points are inserted inside the model and the 3D Voronoi fragments are generated as many as the seed points. At the same time, the breakable linear constraints between the fragments are established. Then, during the dynamics simulation stage, the rigid body fracturing simulation is achieved by processing the dynamics collision such as the collision detection and collision response. In this paper, the method is applied in the rock model simulation with a good effect. The dynamics property of rigid body is ideal. The simulation presents both perfect physical reality and real-time property. As shown in the experimental results, the fracturing algorithm has good universality, which can be applied to the simulation of rock, wall, plaster and other materials. The simulation frames can reach over 60 fps.