The present invention discloses a lead-in device for short-circuiting three-phase transformers, and relates to the technical field of lead-in wiring, including an operating rod and a clamping mechanism, wherein the clamping mechanism includes an insulating rod, a screw, a fixed chuck and a movable chuck, the fixed chuck being fixedly mounted on the top of the screw, the movable chuck being slidably sleeved on the screw, the insulating rod being threadedly connected with the screw by a screw sleeve to drive the movable chuck and the fixed chuck to open and close; the operating rod and the insulating rod are rotatably connected by a swing mechanism to adjust the angle of the clamping mechanism. By rotating the operating rod, the movable chuck can be pressed upward against the equalizing ring, so that the movable chuck and the fixed chuck can cooperate to lock the equalizing ring, the connection is firm and stable, and the problems of swinging, slipping, and virtual connection are solved, and the lead-in wiring operation can be carried out on the ground with high safety; and the operating rod and the insulating rod are connected by a swing mechanism to adjust the clamping angle of the clamping mechanism, so that the equalizing ring can be clamped conveniently.