The utility model discloses a coupler of an insulated rod. The connecting device of the insulated rod comprises a coupler sleeve, an elastic cup-shaped contact, a connecting spring and a hollow bolt. The upper end and the lower end of the coupler sleeve are provided with two hollow cylinders respectively. A metal partition layer is arranged between the upper hollow cylinder and the lower hollow cylinder. Tow cylindrical holes of different diameters are formed in the middle of the metal partition layer. The elastic cup-shaped contact and the hollow bolt are installed in the two cylindrical holes of the different diameters respectively. The connecting spring is arranged between the cup-shaped contact and the hollow bolt. The coupler of the insulated rod has the advantages of being firm, durable, simple in structure, convenient to use and the like. The condition that in the prior art, the insulated rod is connected in a threaded mode, so that thread alternating, slipping and the like occur is avoided. Besides, an electroscope, a discharging rod and other tools can be provided with standard connectors matched with the coupler of the insulated, so that every time the insulated rod is used, a user only needs to carry one set of standard tools, and therefore the work efficiency of power operation staff is greatly improved.