The invention belongs to the field of forestry equipment, and in particular discloses a ring-cutting seedling excavator which comprises a screw, a connecting rod, a rotating shaft, two chassis and twosupporting plates, the two chassis can combine to form rectangular frame; one end of the two chassis is hinged, and the other end of the two chassis can be detachably connected, the two supporting plates can combine to form a rectangular frame, one end of the supporting plate is hinged and the other end can be detachable connected; a two-way motor and a thread part are arranged on the supportingplate, and the output shaft of the two-way motor is connected with one end of the rotating shaft, and the other end of the rotating shaft is slid connected with the other end of the screw; the screw threads through the threaded part and is matched with the screw thread; the screw and the rotating shaft do not generate relative rotation, and the other end of the screw is provided with a threading tool, and the chassis is hinged with one end of the connecting rod, and the other end of the connecting rod is hinged with the supporting plate. The excavator is conveniently used to excavate seedlingsand reduces manual labor.