A multi-spindle gearbox system includes a gearbox, a gear assembly, an output sleeve spindle, and a cable receiving barrel. The gearbox includes a base and a sealing cover covering the base. The sealing cover forms a hollow box space together with the base receiving the gear assembly therein. The base defines an assembly hole therethrough. The sealing cover defines a guiding hole corresponding to the assembly hole of the base. The output sleeve spindle is hollow and cylindrical with one end thereof assembled to the assembly hole of the base corresponding to the gear assembly. The cable receiving barrel is assembled within the gearbox. One end of the cable receiving barrel connects with the assembly hole and the other end of the cable receiving barrel passes through the guiding hole and is exposed to an outer side of the sealing cover.