Method of manufacturing carbon fiber paper used in gas diffusion layer of fuel cell

The present invention (i) a process for producing a carbon fiber web (Web) by dispersing the carbon fibers in the form of short fibers in water or an aqueous solution and then lifting the carbon fibers with a screen and then dehydrating them; (Ii) a process of impregnating the carbon fiber web with a thermoplastic resin; (Iii) a process of crosslinking and stabilizing a carbon fiber web impregnated with a thermoplastic resin by supporting it in sulfuric acid; And (iii) carbonizing the crosslinked and stabilized carbon fiber web to produce carbon fiber paper. The present invention significantly improves the electrical conductivity of the manufactured carbon fiber paper while effectively preventing the problem that the mechanical properties of the carbon fiber paper are significantly deteriorated as the thermosetting resin impregnated in the conventional carbon fiber web is carbonized. The carbon fiber paper produced by the present invention has excellent mechanical properties and electrical conductivity at the same time， and is therefore particularly useful as a material for producing a gas diffusion layer of a fuel cell.