The utility model belongs to an electric system equipment test device and provides a device for testing super-long gas insulated switchgear (GIS) main loop resistance. The connection of the test wire of the device is that a loop resistance tester output voltage wire U+ and U- are connected with the two ends of a to-be-tested GIS bus conductor; a test current wire I+ is reliably connected with the connection point e of a GIS bus cylinder housing; a not less than 25mm<2> copper wire is disposed on the loop resistance tester output voltage U+ to reliably connect the GIS conductor and the housing; the GIS bus cylinder housing is provided, wherein the flanges of the cylinder housing are connected via bolts and copper bars; and the GIS bus conductor serves as a component to finally form the test device. The device of the utility model is suitable for testing super-long GIS main loop resistance with 800 KV and less than 800 KV, is accurate and reliable in test data, enables time, manpower and material resources to be reduced, helps to reduce the cost of testing the 800 KV super-long GIS main loop resistance, to shorten the construction period and to improve the mounting quality of GIS equipment, and helps to provide accurate test data for a preventive test.