In order to unify the discrimination method of failure members in progressive collapse analysis for large-span spatial grid structures, the selection method of probable range for the important members was put forward based on the failure modes of buckling and strength. A novel analytical method, known as multiple responses, was then introduced based on the primary scope. This proposed method was eventually implemented in the mechanical analysis of the main stadium for the Universiade Sports Centre. The arrangement of the important members for folded-plane latticed shell structures was established. It is found that the computation results agree with the design results well. It is shown that the novel analysis approach is suitable for the evaluation of the structural performance of the important members in large-span spatial grid structures. The deficiency of current methods that single structural response is only considered is made up. The problem that the unified standard is not given for the members to be removed of spatial grid structures in progressive collapse analysis is also solved. Moreover, the alternate load path method will have extensive applications.