The structural characteristics of rocket sleds directly affect the accuracy and credibility of rocket sled tests. Rocket sled structure design faces increasingly stringent lightweight design requirements. However, uncertainties from material properties, processing and manufacturing, and service environments restrict the safety of rocket sled structure design. How to balance the economy and safety of rocket sleds is an important content of rocket sled structures. In this paper, topology optimization is used as a design method to carry out reliability topology optimization design of rocket sled structure under displacement constraints, in order to meet the lightweight and safety requirements of rocket sled structure, and to consider the uncertainty characteristics of material properties and service environment. On the basis of full-time dynamic simulation analysis, the severe state load cases are extracted, and the reliability topology optimization model of rocket sled structure is established based on the SIMP method. The influence of uncertainty is quantified by interval model, and the sensitivity of reliability index to pseudo density is solved by adjoint vector method. The reliability topology optimization design of rocket sled structure under uncertainty is realized. The results show that the reliability topology optimization design results of the rocket sled structure under displacement constraints in this paper meet the requirements of the vibration characteristics of the rocket sled structure, and have reference significance for the refined and lightweight design of the rocket sled structure.