The invention discloses an extra-high voltage transformer station ultrahigh frequency partial discharge anti-electromagnetic interference testing method and mobile platform. The technical scheme provided by the invention is as follows: a shielding band is arranged on a GIS device, the shielding band is provided with a detection port, and the detection port is opposite to a metal tape opening on the GIS device; an ultrahigh frequency sensor is arranged at the detection port, the ultrahigh frequency sensor is in close contact with the GIS device, the ultrahigh frequency sensor is sleeved by a shielding bag, and the bag port of the shielding bag is in close contact connection with the shielding band outside the detection port so as to form a shielding cavity; and the ultrahigh frequency sensor is connected with a detection instrument on a mobile casing through a connecting line, the lower portion of the mobile casing is provided with a storage battery pack, and the detection instrument processes signals emitted by the ultrahigh frequency sensor and displays a detection result or uploads the display result to a host computer. According to the invention, the ultrahigh frequency sensor is arranged in an enclosed space formed by the GIS device and a shielding apparatus, such that interference of external electromagnetic waves is effectively inhibited, and high detection sensitivity is ensured.