The existing slicing algorithms for metal laser solid forming (MLSF) were analyzed. A rapid slicing algorithm based on dynamic topological reconstruction for STL (stereo lithography) model was proposed. According to geometrical information of the triangular facets and the slicing thickness, the times of traversing the triangular facets are reduced by using grouping matrix method. The times of intersecting between the slicing plane and the triangular facets are reduced by using the local dynamic topological construction algorithm. The fact that the topology of triangles between two slicing layers is similar or the same, a dynamic topological reconstruction algorithm is built. The time of searching adjoining relation among triangles is reduced, the efficiency of the slicing algorithm was increased effectively. On the basis of the algorithm, the software with independent intellectual property rights was developed using Visual C++ and OpenGL.