The invention discloses an oil-immersed type testing transformer-based residual electricity automatically discharging device and belongs to the technical field of high voltage insulation. The oil-immersed type testing transformer-based residual electricity automatically discharging device comprises a conducting contact, a lifting conducting bar, an external insulating case, an internal conductingsupport, an insulating base, a fixed support rack, movable support wheels, a control module, a power module, a protecting circuit and a switch state detecting circuit. The working process of the oil-immersed type testing transformer residual electricity automatically discharging device comprises that the switch state detecting circuits uninterruptedly detects the switch state of a high-voltage testing console and transmits state variables to the control module for controlling the conducting bar to move up and down, and the conducting contact connected with the lifting conducting bar is in fullcontact with the high-voltage output end of a testing transformer so that residual electricity can be discharged via the conducting contact, the lifting conducting bar, the internal conducting support and a ground wire. The oil-immersed type testing transformer-based residual electricity automatically discharging device achieves automatic conduction and discharge of residual electricity of the high-voltage output end of the testing transformer, has the advantages of being convenient to assemble and disassemble, simple in structure and the like, and compared with existing manual discharging methods, can greatly reduce the testing risk and be widely applied to discharging residue electricity of oil-immersed type testing transformers in the field of high voltage insulation.