The invention discloses an electrostatic probe-based GIL insulator 
surface charge on-line 
monitoring system, which comprises an electrostatic probe; the electrostatic probe comprises three fan-ring-shaped red 
copper electrodes uniformly distributed along the circumferential direction of the electrostatic probe, fan-ring-shaped 
epoxy insulators are fixed between the fan-ring-shaped red 
copper electrodes, and the 
epoxy insulators are fixedly connected with an insulator; the fan-ring-shaped red 
copper electrodes are connected with resistance 
voltage dividing arms, the resistance 
voltage dividingarms are electrically connected with operational amplifiers, and the operational amplifiers are electrically connected with induction potential 
data acquisition devices used for detecting the fan-ring-shaped red copper electrodes. The electrostatic probe is pre-installed near a ground 
electrode of a GIL insulator, probe induction 
voltage is stored in real time through the 
data acquisition system,and the 
surface charge accumulation condition can be monitored in real time; the electrostatic probe measures 
surface charges in a non-contact manner, the original 
surface charge distribution is not damaged, and the probe adopts a circular ring design, so that the 
distortion of the probe to an original 
electric field can be effectively reduced.