Abstract: Due to the existence of oxygen-containing functional groups, GO has unique permeability to gas.Leak ele-ment is an essential apparatus, which is used to accurately calibrate the ultralow leak rate.In this paper, graphene oxide(GO) membranes are assembled by typical vacuum filtration method and then assembled into leak elements.Gas perme-ance of GO membrane was measured by Leybord L300i helium mass spectrometer leak detector.The relationships be-tween helium permeance and GO membrane thickness as well as the pressure differential across the membrane are studied.A critical GO membrane thickness is demonstrated:when the thickness is less than 600 nm, the leak rate of the GO mem-brane is inversely exponential to the membrane thickness, but the leak rate is negative linear to the thickness when the mem-brane is thicker than 600 nm.Based on the special properties of GO membrane, a standard leak element is developed.And the as-prepared GO membranes leak element is employed as an ultra-low standard leak.