Abstract: Through field test data and the data existed, the article uses FLAC-3D software to simulate and analyze the mechanism of CFG pile composite foundation settlement laws proposed high-rise buildings and underground garage space, as well as the role of the relationship between the two in terms of the deformation of the building. The obtained data is compared by simulation of settlement of CFG pile deformation and actual measurement, which obtained the actual CFG pile settlement distribution,has the instruction significance to the design of CFG pile composite foundation under similar conditions.