Abstract: Abstract of the disclosure The present invention provides a method and an apparatus for a glow discharge plasma surface treatment of flexible sheet materials under atmospheric pressure. The apparatus comprises electrodes, a single plasma-gas flow channel, uniform gas inlet-and-outlet devices, gas-seal devices for the horizontal movements of sheet materials and reel devices, so as to attain an uniform distribution of plasma gases in the gap between electrodes. As a result, not only a great amount of expensive plasma gas is saved, but also an uniform glow discharge plasma is generated at the lowest input power to obtain a good quality of uniform plasma treatment with continuous processing and high production.