Abstract: A deep excavation located in Kunming City is taken as an example. The feasibility, deformation and stress change laws of large circle beam supporting structure used in the deep peaty soils are analyzed. The displacement and stress monitoring results of excavation supporting structure show that the large circle beam supporting structure can overcome the low anchoring force of anchors and relaxation deformation and have reasonable force performance, convenient construction and economic advantages. Compared with that of excavation in deep mucky soft, the deformation of excavation in peaty soil is larger. It will provide a good reference for other similar projects.