The invention discloses an electromagnetic operating mechanism and a vacuum circuit breaker. The electromagnetic operating mechanism comprises a movable iron core which is provided with a limiting clamping groove at the periphery thereof; a shell assembly, wherein the movable iron core is movably inserted into the shell assembly; and a non-magnetic repulsion disc and a repulsion coil both of whichare arranged in the shell assembly and are movably arranged on the movable iron core in a sleeving manner. One end of the repulsion coil is positioned on the supporting part of the shell assembly, and the other end of the repulsion coil is in contact with one end of the non-magnetic repulsion disc. The two ends of an elastic piece elastically act on the other end of the shell assembly and the other end of the non-magnetic repulsion disc respectively so as to exert the elastic force to the non-magnetic repulsion disc, wherein the elastic force is moving towards one side of the repulsion coil.A limiting ball is in split contact with or movably connected with the edge of the inner ring of the non-magnetic repulsion disc and is used for being embedded, clamped and matched with the limiting clamping groove. According to the electromagnetic operating mechanism, the closing maintenance is completed through the cooperation of the repulsion coil, the non-magnetic repulsion disc, the elastic piece, the limiting ball and the limiting clamping groove. The mechanism has fewer components, and is simple in structure and more reliable in operation.