In recent years, insulating faults caused by surface discharge of insulators are more common. Impulse withstand voltage detection and partial discharge detection under impulse are effective means for insulation evaluation and diagnosis.In this work, PD diagnosis was performed under standard oscillating lightning impulse (OLI), oscillating switching impulse (OSI) and alternating current (AC) voltages on a 110 kV gas insulated switchgear (GIS) bus model with artificial particles on the insulator surface. The results demonstrated that PDs under OIVs occurred at the rising slopes of the oscillating periods. Most of the reverse polarity pulses were found under OLI voltage, few were found under OSI voltage, and none were found under AC voltage. PD sequences excited from the negative needle point were composed of small and compact pulses. In contrast, positive-point excited PD sequences were composed of larger pulses but fewer of them. These results prove that the defects of particles on the insulator surface are more sensitive to OIVs than to AC voltage.