The utility model discloses a self-expanding plastic bracket. The self-expanding plastic bracket comprises a drainage tube; the drainage tube comprises a near end and a remote end; more than one cage-shaped convexes with telescopic elasticity are arranged between the near end and the remote end of the drainage tube; each cage-shaped convex comprises more than two connecting ribs with telescopic elasticity; gaps are formed between the connecting ribs; the interior and the exterior of the drainage tube are communicated through the gaps; drainage tube imaging rings are respectively arranged at the remote end of the drainage tube and in the first cage-shaped convex close to the remote end, and fixed on the inner wall of the drainage tube. The utility model further discloses a bracket adaptive introducer adaptive to the self-expanding plastic bracket; one end of an inner tube is connected with a boosting tube; the other end sequentially penetrates through a front handle, a screw cap, an outer tube, a straightening tube and the self-expanding plastic bracket; an outer tube imaging ring is arranged on the outer wall of the outer tube; an inner tube imaging ring is arranged on the outer wall of the inner tube, and is propped against the drainage tube imaging ring to form push of the inner tube to the self-expanding plastic bracket.