The application discloses an OPGW (Optical Fiber Composite Overhead Ground Wire) terminal reserved-cable device of an ultrahigh-voltage transformer substation and the device prevents a problem of inter-turn discharge electric-corrosion strand breakage of an optical cable, which exists in a wound optical cable and is caused by inter-turn induction voltages and prevents a problem of galvanic corrosion strand breakage generated by contact of the optical cable and a seizing iron wire and thus the device is safe and reliable and beautiful. The device includes a nonmetal attic base and a nonmetal shrouding disc. The nonmetal attic base includes an inner plate and a winding column, which are formed integratedly. The inner plate is on the positive face of the nonmetal attic base. The winding column stands at the center of the inner plate. An OPGW terminal reserved cable is wound on the winding column and four cable-limiting distance adjustment holes are uniformly distributed at the edge of the inner plate. The nonmetal shrouding disc includes an outer plate. Four cable-limiting distance adjustment holes are arranged in the outer plate, corresponding to the four cable-limiting distance adjustment holes in the inner plate. Cable-limiting bolts are inserted into the cable-limiting distance adjustment holes so that the inner plate and the outer plate are fixed.