The invention discloses a method for judging whether a reactive compensation device lightning arrester is electrified. One end of a digital voltmeter is connected on a self-manufactured insulating coil, and the other end is connected to a grounding end of the reactive compensation device lightning arrester, so as to measure a suspension voltage to ground of the self-manufactured insulating coil; positions and angles of the self-manufactured insulating coil and an electric reactor are changed; if a voltage numerical value of the digital voltmeter is large and changes greatly, it indicates that the electric reactor is electrified, and the reactive compensation device lightning arrester is electrified and can be connected with a lightning arrester testing instrument for testing; and if the voltage numerical value of the digital voltmeter is small and does not change significantly, it indicates that the electric reactor is not electrified, and the reactive compensation device lightning arrester is not electrified. The method can be used for judging the electrified conditions of outdoor 35kV, 66kV voltage-class reactive compensation device lightning arresters directly without connecting an electrified testing instrument, saves manpower, and can effectively shorten operating time and improve related working efficiency.