Abstract: When low subgrade on deep soft ground in high speed railway is treated with CFG pile-wet composite foundation,it cannot ensure the long-term stability under cyclic loading and the pile cannot give full play to the advantages of high bearing capacity.So the sparse pile-raft foundation structure is applied in low subgrade on deep soft ground in ballastless track high-speed railway,and the characteristics of settlement deformation of structure,pile-soil stress and the loading deformation of raft are tested through choosing representative working points.Moreover,the design calculation method is investigated and some proposal on engineering application need further in-depth studys.