A Sobol global sensitivity analysis method based on radial basis surrogate model was proposed to analyze the influence of design parameter uncertainty on performance output uncertainty of solid rocket motor system in design space and to break through the prominent problems of high fidelity solid rocket motor simulation model parameter design, such as high cost and long time. In this paper, a Sobol global sensitivity analysis method based on radial basis surrogate model is proposed for solid rocket motor design parameters. Considering 10 design parameters that have great influence during the design process, the global sensitivity analysis results of 7 output performance indicators that are of major concern to the system as a whole are obtained, providing guidance for further design optimization of the solid rocket motor system. The results show that the combustion rate, cylinder length of combustion chamber, initial throat diameter and characteristic velocity are the main design parameters that affect the output performance of solid rocket engine.