Some embodiments of the present disclosure discloses a 5G millimeter-wave novel dual-polarized horn antenna. The antenna includes an upper plate, a lower plate, a front plate, a rear plate and a cover plate, the cover plate is disposed on a rear end of the antenna, the front plate and the rear plate are disposed between the upper and lower plate, an excitation cavity structure is defined in the upper plate, the lower plate, the front plate, the rear plate and the cover plate, an excitation cavity with a rectangular cross section is formed in the cavity structure, the cross section of the excitation cavity is gradually reduced from right to left and then kept unchangeable, the left end of the excitation cavity is sealed through the cover plate, the upper plate, the lower plate, the front plate and the rear plate in the excitation cavity all include a curve ridge.