The invention provides a swelling soil cutting deep-layer drainage structure, so that water level reduction and quick drainage functions of deep ground water are achieved, and meanwhile the construction difficulty and project investment are effectively reduced. The structure comprises shafts longitudinally arranged in a swelling soil foundation on the outer side of a roadbed structure at intervals, vertical drainage bodies longitudinally arranged in the positions, between the adjacent shafts, of the swelling soil foundation at intervals, longitudinal drainage bodies transversely arranged in the positions, at the bottoms of the shafts, of the swelling soil foundation at intervals, engaged jet grouting piles arranged in the positions, between the adjacent shafts, of the swelling soil foundation and located on the outer sides of the vertical drainage bodies and the longitudinal drainage bodies, and pitching inclining drainage bodies arranged in the positions, below the roadbed structure,of the swelling soil foundation and pitching and inclining downwards to the bottoms of the shafts.