Abstract: Because of the difference between loess collapsible degree of different areas and the difference in the construction technology of pile, there exists difference in the physical and mechanical properties of the composite foundation formed using the same distance between two holes processing collapsible loess. Therefore, the distances between two hole of pile, the compacting coefficient, the bearing capacity of compound foundation characteristic values and other major design index should be determined based on the purpose of the foundation treatment of collapsible loess, the degree and construction technology comprehensive factors.