In order to optimize the processing scheme of medium compression soil foundation, the short pile-net composite foundation deformation characteristics is explored using the method of field test and theoretical analysis on a test section of Ganlong high-speed railway, and it's compared with the natural foundation. It is shown that the settlement of composite foundation reinforced area is 62%~75% of total settlement, the lateral displacement mainly occurred in preloading soil loading period and 20m depth is the main layer. Under similar conditions, the main stage of settlement, the main settlement layer thickness and settlement of cross section are quite different between composite foundation and natural foundation. The results show that the short pile-net composite foundation can effectively control the deformation of the medium compression soil foundation, which can provide reference for similar projects.