In order to investigate the influence law of partial discharge (PD) propagation distance and angle, light guide rod optical sensor and other factors on the PD optical signal propagation characteristics of gas insulated switchgear (GIS), the optical simulation software TracePro is used to establish a GIS simulation experimental tank, set up a number of detection surfaces and detection points, analyze the GIS internal optical signal propagation law, and study the change law of light intensity received by the optical sensor under different PD locations.