The invention discloses a traction assembly for a gooseneck of a semi-trailer, relates to the field of damping systems, and particularly relates to improvement of traction assemblies with damping functions for goosenecks of semi-trailers. The traction assembly for the gooseneck of the semi-trailer is exquisite in structure, good in connection stability, high in limit capacity and convenient to adjust. The semi-trailer comprises a balance beam and the gooseneck. The gooseneck is connected to the upper side of the balance beam in a floatable manner. The traction assembly comprises a horizontal limit component. The horizontal limit component comprises a draw bar and a pair of fixing seats, the two fixing seats are fixedly connected onto the balance beam and the gooseneck, and two ends of the draw bar are hinged to the two fixing seats. A pair of side bosses is fixedly connected to two sides of the balance beam, a pair of side frames is fixedly connected to two sides of the gooseneck, an opening is formed in the side, which faces the balance beam, of each side frame, and the side bosses are accommodated in the openings of the side frames. The traction assembly has the advantages of exquisite structure, good connection stability, high limit capacity and convenience in adjustment.