Abstract: In this paper, some physical properties of tungsten powder used for Ba-W cathode have been analyzed in detail by SCXA-733 electronic probe scanning microscope and SKC-2000 light emission particle size measuring instrument, meanwhile, the relation between the fracture morphology and surface character and the current density of Ba-W cathode has been tested. The physical theory of particle surface has been used to illustrate the inherent relation of physical properties of tungsten powder used for Ba-W cathode. It is of practical significance for classification method of powders and for study of materials.