The invention relates to a connecting apparatus used for transformer winding deformation detection. The connecting apparatus comprises a ceramic sleeve pressing ring plate with an open hole and a fixed hole, a conveying cover plate with an open hole and a welding threaded rod, an insulating ceramic sleeve, a detection copper bar and a detection lead cable; the insulating ceramic sleeve passes through the open hole in the conveying cover plate; a welding bolt on the conveying cover plate passes through the fixed hole in the ceramic sleeve pressing ring plate to be fastened by a nut; the detection copper bar passes through the open hole and the insulating ceramic sleeve on the ceramic sleeve pressing ring plate and extends for one parts from the lower end of the insulating ceramic sleeve andthe upper end of the ceramic sleeve pressing ring plate respectively; and one end of the detection lead cable is connected with a copper head or a wiring copper bar led from each phase of a transformer while the other end is connected with the lower end part of the detection copper bar. By virtue of the connecting apparatus, the transformer and detection equipment can be connected conveniently, and the deformation condition of the transformer winding in the conveying process can be detected in real time; and the connecting apparatus is simple in structure, small in size, convenient to detach,simple in operation, reusable, and economical and practical.