The invention relates a GIS (gas insulated substation) optical current transformer installing device which is used for installing an electrical cable and an optical cable at the same time. The GIS optical current transformer installing device comprises an electrical cable installing support, an optical cable accommodating box and an optical cable locking connector, wherein the electrical cable is fixed on the electrical cable installing support; the optical cable accommodating box is fixed on the electrical cable; and the optical cable is coiled inside the optical cable accommodating box and is led out through the optical cable locking connector. Compared with the prior art, the GIS optical current transformer installing device has the advantages of high stability, good repeatability and the like.