The invention discloses an SF6 gas-insulated metal-enclosed complete alternating-current voltage-withstanding and partial-discharge test device. The device comprises a reactor tank, a transition tank, a right-angle tank, a capacitor tank and a three-way butt joint tank; the electric reactor tank, the transition tank, the three-way butt joint tank, the right-angle tank and the capacitor tank are sequentially isolated by basin-type insulators, and each tank is filled with SF6 gas as an insulating medium. According to the complete test device, SF6 gas is used for insulation, the device is light in weight and small in size, the limitation of lifting tools, placing places and the like in a GIS hall of an underground powerhouse can be effectively solved, meanwhile, a high-voltage loop adopts a totally-closed tank structure, other external electromagnetic interference and pulse signals in a plant station can be effectively shielded, a coupling capacitor for partial discharge test is arranged, the partial discharge test can be carried out by adopting the principle of a pulse current method, and the partial discharge test device has obvious advantages on partial discharge analysis in an insulation verification test after GIS handover test or GIS maintenance.