The invention discloses a tapping machining device of a hexagon nut. The device comprises a vibration disc, an L-shaped feeding rail, a discharging port, a conveying guide rail, a material pushing mechanism and a material receiving turntable mechanism, wherein the vibration disc is used for conveying a hexagon blank of the thread to be machined, the discharging port is connected with the vibrationdisc, the conveying guide rail is arranged at the upper end of the L-shaped feeding rail, the material pushing mechanism is arranged on the right side of the bottom of the L-shaped feeding rail, andthe material receiving turntable mechanism is arranged on the left side of the bottom of the L-shaped feeding rail; the material pushing mechanism can push the hexagon blank at the bottom of the L-shaped feeding rail to be connected with the right side of the material receiving turntable mechanism, a material ejecting mechanism and a tapping mechanism are arranged in the front and back part of thematerial receiving turntable mechanism correspondingly, wherein the material ejecting mechanism is used for ejecting the hexagon blank in a tapping machining process, the tapping mechanism is used for tapping; and a material pressing mechanism used for pressing the hexagon blank is further arranged above the material receiving turntable mechanism. According to the device, feeding, tapping and discharging are realized, a continuous machining production is realized at the same time, and the tapping efficiency is improved, all-directional fixation is realized in the tapping process, the stability of the tapping is guaranteed, and the production quality of the hexagon nut is improved.