Based on the design calculation of Single pile composite foundation,the computational method of multi-type-pile composite foundation's bearing capacity,compression deformation and soft underground stratum checking are discussed, and it is confirmed by the practical instances. At the same time, in order to eliminate the collapsibility of loess and increase the strength of foundation, the ram dry concrete pile and CFG pile are being used in the ground treatment of collapsible loess zone for the first time, remarkable economic results and application effects have been achieved.