The invention discloses a roadbed structure for spanning a subway on deep and thick soft foundation. The roadbed structure comprises a bearing plate, a trimmer beam and an all-casing drilling cast-in-place pile, wherein the all-casing drilling cast-in-place pile is buried in the foundation, the trimmer beam is arranged above the all-casing drilling cast-in-place pile in a direction parallel to the subway, and the bearing plate is arranged above the trimmer beam along the roadbed direction. The roadbed structure disclosed by the invention not only meets the requirements of settlement control, but also can ensure the stability of the subway under the action of railway construction and long-term dynamic load of the railway.