The invention discloses an experiment device for measuring insulator surface charges. The device comprises a cavity housing internally provided with a hollow cavity. The cavity housing is internally provided with an insulator installation mechanism. The insulator installation mechanism is provided with grounding electrodes, conductors and sliding contacts which are uniformly arranged at two sides in the length direction of the hollow cavity. The grounding electrodes are in sliding connection with the cavity housing along the length direction of the hollow cavity, and the grounding electrodes are in a hollow barrel shape. The conductors are arranged on the middle parts corresponding to the grounding electrodes. The sliding contacts sleeve the corresponding conductors and are capable of sliding relative to the conductors along the length direction of the hollow cavity. The sliding contact on each side is provided with an insulating pull rod. One end, far away from the sliding contact, of the insulating pull rod extends out from the cavity housing on the corresponding side. The experiment device for measuring insulator surface charges is capable of providing convenience for measurement in an insulator scanning process, scanning dead zones are not liable to occur in the charge measuring process, and full-coverage scanning is realized.