A GIS ultrahigh-frequency partial discharge test auxiliary tool comprises an adjusting bolt, an upper claw, an upper main board, a lower main board, a lower claw, a connecting bayonet and a control head. The lower main board is a main body member. The lower end of the lower main board is provided and connected with the lower claw inclined inwards. The upper end of the lower main board is connected and provided with the upper main board through the adjusting bolt. The upper end of the upper main board is connected and provided with the upper claw inclined inwards. The back side of the lower main board is connected and provided with the control head. The lower end of the control head is provided with the connecting bayonet. The GIS ultrahigh-frequency partial discharge test auxiliary tool has the advantages of overall simple structure, convenient operational use, good stability and high reliability. By means of the GIS ultrahigh-frequency partial discharge test auxiliary tool, the time for a GIS ultrahigh-frequency partial discharge test can be obviously shortened. Meanwhile, the hidden trouble existing in equipments can be detected in a timely manner. GIS equipments are thus ensured to run normally. A solid base is thus laid for the safe running of a power grid. Personal safety is further effectively guaranteed.