The invention relates to a device for electronic beams to assist plasma in sputtering coating of a flexibility copper-clad plate, and belongs to the technical field of electronic industry. The device comprises a vacuum chamber and further comprises partition plates, a plurality of electronic beam assisting devices, a plurality of pairs of magnetic control targets, a base material and a running line assembly, all of which are arranged in the vacuum chamber, wherein the running line assembly is used for controlling running of the base material. The running line assembly comprises an unwinding roller, a first guide roller, a first detection roller, a second guide roller, a water cooling drum, a third guide roller, a second detection roller, a fourth guide roller and a winding roller, all of which are sequentially arranged along the base material running path. The multiple pairs of magnetic control targets are arranged in the circumferential direction of the circumferential surface of the water cooling drum. Each of the two sides of each pair of magnetic control targets is provided with one electronic beam assisting device. The unwinding roller, the first guide roller, the first detection roller, the second guide roller, the third guide roller, the second detection roller, the fourth guide roller and the winding roller are located above the partition plates, and the electronic beam assisting devices and the magnetic control targets are located below the partition plates. According to the device, the deposition quality of a metal thin layer is effectively improved, and the binding force between the metal thin layer and the base material is greatly improved.