Aimed at the problem of the sensitivity of design variables in the design of aircraft structures，this paper puts forward a global sensitivity analyzing strategy based on Sobol's method and support vector machine method, and analyzes the parameter sensitivity with Sobol method by taking damage tolerance design to the aircraft overall beam as example, the overall beam cross-section parameters as design variables，and respectively constructing the replacement models of stress intensity factor and structure weight with the application of support vector machine theory. The result shows that the conclusion obtained can provide a guidance for selecting the design parameters and modifying the design variables in the optimization design of the structure.