GIS equipment has become the key equipment of power system. In order to ensure the safe operation of power system, it is very important to monitor the running state of GIS equipment in real time. Therefore, it is very important to detect the effectiveness of the alarm strategy of the GIS ultra-high frequency online monitoring device. This paper proposes an alarm strategy test method for the ultra-high frequency online monitoring device based on the real GIS experimental platform, and the typical insulation of the ultra-high frequency online monitoring device of the three manufacturers. The alarm strategy of the tip and suspension defects is verified, and the application of the alarm strategy test method is realized.