The invention discloses a transformer thermometer embedded groove replacing device. The device comprises a body cover, wherein a lower end of the body cover is provided with a compaction plate and a fixed magnet capable of compacting the compaction plate on a transformer, the body cover is provided with a cut valve and is internally provided with an outer cylinder, the outer cylinder is internallyrotatably equipped with an inner cylinder, a lower end of the inner cylinder is equipped with an inner clamping block, the outer cylinder is fixedly equipped with a driving wedge capable of driving the inner clamping block to clamp an embedded groove inwards when the inner cylinder rotates, the inner cylinder and the outer cylinder are provided with a locking mechanism capable of realizing relative locking of the two, an inner centering device of the inner cylinder is further comprised, and a lower end of the centering device is equipped with a grasping mechanism capable of grasping a thermometer. The device is advantaged in that oil release, oil stop and standing operation for the transformer are not needed, the work time is greatly reduced, work efficiency is greatly improved, and the main transformer power failure time is saved.