In the soft ground treatment by vacuum preloading, the horizontal and vertical influence scope caused by the vacuum preloading is essential to the soft ground treatment project. Based on the CSR rail vehicle maintenance-built base’s large area soft ground treatment project, according to the monitoring data of surface settlement, vacuum degree and pore water pressure of different depths in the loading area, as well as the surface settlement and horizontal displacement outside the loading area, we get the influence scope of soft ground treatment by vacuum preloading which can provide reliable data and serve as reference for the design and construction of similar projects in the Pearl river delta region.