NOVELTY - A carbon fiber paper is made by dissolving thermoset amine-catalytical phenolic resin into absolute ethyl alcohol to make phenolic resin ethanol solution, steeping carbon fiber mat into phenolic resin ethanol solution to obtain carbon fiber mat phenolic resin prepreg, processing mold pressing on pressure equipment to obtain carbon fiber embryonic plant, processing low-temperature carbonizing treatment for carbon fiber embryonic plant under nitrogen protection, and processing carbonizing treatment for carbon fiber paper processed under nitrogen protection.    USE - Making of carbon fiber paper used as substrate materials for fuel cell gaseous diffusion layer of proton exchange film.    ADVANTAGE - The method obtains carbon fiber paper which has relatively high poriness, air permeability, electrical conductivity and drafting strength.    DETAILED DESCRIPTION - A carbon fiber paper is made by dissolving thermoset amine-catalytical phenolic resin into absolute ethyl alcohol to make phenolic resin ethanol solution, selecting carbon fiber mat with standard of 20-5 g/cm2 containing polyacrylonitrile carbon fiber as short-cut carbon fiber with mass fraction of 70-90% and polyvinyl alcohol (PVA) as binding agent with mass fraction of 10-30%, steeping carbon fiber mat into phenolic resin ethanol solution to obtain carbon fiber mat phenolic resin prepreg and controlling steeping volume according to volume ratio of 1:0.25-0.5 between short-cut carbon fiber and resin carbon, taking 2-5 layers of carbon fiber mat phenolic resin prepreg, processing mold pressing on pressure equipment to obtain carbon fiber embryonic plant at pressure of 0.5-5 MPa and temperature of 120-170 degrees C for 10-40 minutes and controlling thickness of carbon fiber embryonic plant in 0.18-0.42 mm during mold-pressing time, processing low-temperature carbonizing treatment for carbon fiber embryonic plant under nitrogen protection, obtaining low-temperature carbonizing material, controlling temperature of low-temperature carbonizing between 500-900 degrees C and controlling heating speed rate of carbonizing between 0.5-5 degrees C/minute for 0.2-2 hours, steeping low-temperature carbonizing material into phenolic resin ethanol solution, controlling steeping volume according to volume ratio of 1:0.5-0.8 between short-cut carbon fiber and resin carbon, obtaining twice-time steeping material, drying at low temperature of 30-70 degrees C and solidifying for 15-120 minutes at 120-175 degrees C, and processing carbonizing treatment for carbon fiber paper processed under nitrogen protection at 900-1500 degrees C for 1-2 hours, controlling heating speed rate of carbonizing treatment between 0.5-5 degrees C/minute and obtaining carbon fiber paper used by fuel cell gaseous diffusion layer.