The invention discloses a liquid and gas isolation plate which is integrally of a disc-shaped structure and is integrally made of high-strength MC (monomer casting) nylon materials. A conductor via hole (2) is arranged in the center of a disc, an oil side for isolating oil of a transformer and a gas side for isolating SF6 gas are respectively arranged on two sides of the disc of the isolation plate, umbrella skirt grooves (3) are respectively arranged on the oil side and the gas side of the disc of the isolation plate and are staggered with one another, depths of the umbrella skirt grooves on the oil side are different from the umbrella skirt grooves on the gas side of the disc of the isolation plate, and the umbrella skirt grooves at ends of the oil side are deeper than the umbrella skirt grooves at ends of the gas side. The liquid and gas isolation plate has the advantages that a pressure-welding sealing structure is arranged between the liquid and gas isolation plate and a metal flange, sealing rings, reserved gaps and fillets are arranged at three contact joints of the metal flange, the oil of the transformer and the gas, and accordingly risks of insulating flashover are reduced while the sealing performance is guaranteed.