With the development of new theory, new technology and new material for weapon system, rocket sled is more and more widely used. In this paper, a dynamic analysis model of sled-pulley system is established for two-track rocket sled system. An optimization method is established for simplifying the three-dimensional sled model. The dynamic equations of rocket sled considering damping, rail clearance and irregularity are derived and solved. The results obtained by the proposed simulation method are basically consistent with the experimental results, which verifies the rationality of the proposed method. The proposed method is of great theoretical and practical significance for the calculation of sled dynamic characteristics, sled design and load prediction.