NOVELTY - A fuel cell electrode diffusion layer carbon paper comprises 45-55 wt.% polyacrylonitrile fiber, 15-35 wt.% polyacrylonitrile pulp platinum fiber, and 20-30 wt.% carbon fiber. The carbon paper is prepared by pulping, slurry preparing and using inclined wire paper machine or side flow circular net papermaking machine for wet papermaking process papermaking, hot-pressing at 230-280 degrees C for 3-90 seconds, and processing for 2-3 hours in inert atmosphere and high temperature of 1800-2200 degrees C.    USE - Carbon paper used for fuel cell electrode diffusion layer.    ADVANTAGE - The carbon paper has good strength and uniformity, relatively high air permeability and excellent conductivity; and the production technology is simple.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of fuel cell electrode diffusion layer carbon paper comprising:    (A) adding carbon fiber into a dispersing barrel with stirrer, adding water, making the concentration of carbon fiber 0.5-0.8 wt.% in water, adding dispersant and stirring pulp to uniformly dispersed in water phase to form carbon fiber slurry;    (B) adding polyacrylonitrile fiber into the dispersing barrel with stirrer, adding water, making the concentration of polyacrylonitrile fiber 1.5-2.5 wt.% in water, adding dispersing agent and fully stirring so that polyacrylonitrile fiber is uniformly dispersed in water phase to form polyacrylonitrile fiber slurry;    (C) adding polyacrylonitrile pulp platinum fiber into beating machine containing water, where fiber concentration in water is 2-3%, pulping for 10-20 minutes, then pulping again for 30-60 minutes, and until completely dispersed fibers, no small point and test slurry pulp beating degree is 45-65 degree SR of a cutter;    (D) mixing the three slurries in all a slurry tank, adding water till the concentration is 1.09-2.0%, adding dispersant to a viscosity of 58-65 seconds to obtain mixed slurry, and placing the mixed slurry to slanting paper or side flow circular net papermaking machine reading the unit area of 100-125 g/m2 of the total weight of the base paper in step (F), and paper cutting to size;    (E) putting into a flat vulcanizing machine at 230-280 degrees C hot pressure for 30-90 seconds; and    (F) forming the carbon paper in high temperature carbonization furnace under inert atmosphere, carbonizing for 2-3 hours at 1800-2200 degrees C to obtain the carbon paper.