The utility model discloses a dedicated box for an instrument for detecting a ground resistor of an electric transmission line, and the dedicated box mainly consists of a box body and a box cover. The interior of the box body is partitioned into at least two parallel wire-coil cavities and at least one instrument cavity. The centers of the wire-coil cavities are vertically provided with pay-off disc supports, and the pay-off disc supports are sleeved by pay-off discs which are wrapped by cables. The cables on the pay-off discs are led out from a side wall of the box body, and the end parts of the cables are connected with wiring clamps. The interior of the instrument cavity is provided with a quakeproof sponge, and the instrument for detecting the ground resistor of the electric transmission line is placed in the instrument cavity. Moreover, the cables of the two pay-off discs are respectively connected with the instrument for detecting the ground resistor of the electric transmission line through plugs. The central cavities of the pay-off discs are sleeved in the cylindrical pay-off disc supports. The upper surfaces of the pay-off discs are respectively provided with a convex turning handle. The wiring clamps are gavial clamps which can increase the contact areas of the clamps with a grounding body. The plugs are banana plugs which can reduce the wiring resistance of the instrument. The box provided by the utility model is reasonable in structure arrangement, is convenient and reliable in application, improves the work efficiency, and can guarantee the accuracy of measurement data.