The invention discloses an auxiliary tool general for a one-time nuclear phase of a switch cabinet. The tool comprises rollers, two insulation blocks, a connecting rod and a push-pull structure. The two insulation blocks are arranged in parallel and perpendicularly connected with the two ends of the connecting rod respectively, a rotating shaft is arranged at the lower portion of each insulation block, the rollers are connected with the insulation blocks through the rotating shafts, the axis of the rotating shafts is parallel to the axis of a connecting rod assembly, a gear pulley positioningblock is connected to the outer side of the upper portion of each insulation block, a gear pulley is matched with the gear pulley positioning block, the axial positions of the insulation blocks on theconnecting rod are adjustable, the push-pull structure is connected with the connecting rod at the middle of the axial direction of the connecting rod. Due to the fact that the axial positions of theinsulation blocks on a screw are adjustable, it is ensured that the position of the gear pulley positioning block is adjustable, the width between opening top plates on the two sides of the tool is continuously adjustable, the tool can adapt to switch cabinets of different types, the safe and efficient one-time nuclear phase is achieved, and the tool is convenient to assemble, disassemble, use and store, and convenient to carry and transport.