Abstract: The traditional underground excavation method has problems such as high risk, low efficiency, great impact on the surrounding environment, and large investment. It is difficult to apply to construction large underground structures in soft strata or complex environments. In order to solve these problems, a new underground excavation method based on large rigidity support system is proposed. The pipe roof, horizontal beam and vertical column are used to construct a large rigidity support system, each component is constructed by non-excavation method or constructed in small space under the protection of pipe roof, which ensure the construction safety and prevent the stress release of the stratum. After the support system is constructed, bulk excavation can be carried out. Compared with the traditional underground excavation method, the new underground excavation method has the advantages of simple process, high efficiency, low risk, small impact on the surrounding environment and small investment. Numerical analysis and engineering examples verify the feasibility and practicability of the new underground excavation method, provide a new idea for the construction of large underground structures.