In the first, the model of reentry trajectory of tactical ballistic missile was built and simulated. In order to solve the problem of mismatch between the maneuvering model in target tracking algorithm and actual movement of the reentry target, a novel target tracking algorithm based on ballistic missile model was used. When information of missile target's position and velocity at every moment was obtained, the simulation of ideal three-dimensional missile trajectory can be realized with the proportional navigation method. The simulation result shows that with the proposed algorithm, the target can be tracked stably and the missile can be guided accurately.