The construction of large-sized hydropower station is a kind of complicated systems engineering; and the underground carven rock’s stabilization is influenced by some factors. The hierarchy of analyzing underground carven rock’s stabilization is divided on the basis of fuzzy analytic hierarchy process. Hierarchy structure model is established; and the stabilization of four segments underground cavern rock is sorted through analyzing and comparing layer by layer. The example shows that the fuzzy analytic hierarchy process integrating quantitative analysis and qualitative analysis together takes on good reliability and practicability.