Abstract: The basic characteristic of the pulsed power science and technology, which is widely applied to X-ray radiography, inertial confinement fusion and high energy density physics, is energy compressing, both temporally and spatially, to obtain high power density and extreme conditions in temperature, pressure and radiation. Vacuum power flow components are decisive for pulsed power systems. Physical fundamentals, key issues and researching status for vacuum power flow around the world are surveyed in this paper. The gap between object and status is analyzed for vacuum power flow investigations for Z-pinch fusion driver. Opinions and researching suggestions are presented.