Abstract：Soft soil foundation reinforced by tubular pile is a type of rigid cushion composite foundation under flexible base，and it is different from flexible cushion composite foundation under rigid base. As one of the new consolidation type of soft soil foundation，the working performance of tubular pile composite foundation is not exactly known in design and construction the working performance of tubular pile composite foundation is studied and the composition and working mechanism of the tubular pile composite foundation are also analyzed. Finite element method is adopted to study cushion setting by imitating one section of the composite foundation of a freeway. The differences between composite foundation under road and composite foundation under rigid base are pointed out；and some reasonable suggestions about cushion treatment for the engineer are put forward，which can be used in similar engineering.
