The invention provides a hanging device for a cantilever casting hanging basket. The hanging device consists of a nut 1, spherical washers 2, a double-end lead screw 3, a conversion connector 4, a steel plate hanging belt 5, a pin shaft 6, a nut 7 and a nut 8, wherein the conversion connector 4 consists of a cross beam plate 9, a side hanging plate 10 and a side hanging plate 11; vertically communicated bolt holes are formed in the other ends, opposite to the beam plate 9, of the side hanging plate 10 and the side hanging plate 11; the double-end lead screw 3 is connected to one end of the conversion connector 4 by the nut 7 after penetrating through the beam plate 9, and the steel plate hanging belt 5 is connected to the other end of the conversion connector 4 by the pin shaft 6; and the spherical washers 2 respectively serve as washers of the three nuts. The hanging device is characterized in that the steel plate hanging belt plate is connected through the conversion connector; and screw-thread steel bars are not required, but are replaced by lead screws and the nuts, so that the safe hanging can be realized, the dangerous factors are eliminated, the operation is convenient, quick and simple, and the construction efficiency is improved.