The invention discloses a copper wire cut-off device of a power strip assembling machine. The copper wire cut-off device of the power strip assembling machine comprises a cut-off mounting plate, a cut-off motor, a motor support, a gear, a toothed belt, a copper wire guide box, a linear sliding rail, a linear sliding block and a cut-off assembly, wherein the motor support is mounted on the upper plane of the cut-off mounting plate; the cut-off motor is mounted on the lower plane of the motor support and drives the gear to rotate; the gear is engaged with the toothed belt which is fixed to one lateral face of the copper wire guide box; copper wires penetrate the copper wire guide box; the linear sliding rail is mounted on the lower plane of the copper wire guide box, the upper plane of the motor support is provided with the linear sliding block corresponding to the linear sliding rail, and the linear sliding block and the linear sliding rail are matched; a shearing mounting plate of the cut-off assembly is mounted on the right side face of the motor support. In this way, the copper wire cut-off device is compact in structure and can replace workers to cut off copper wires automatically, thereby saving labor and having high production efficiency.