A carbon fiber paper manufacturing process and construction has oxidized fiber as raw material needle punched into a construction of 0.1.about.20 mm thick, 5.about.500 g/m2 oxidized fiber felt of weight, then impregnated in high density epoxy, hot compressed and hardened, then finally carbonization processed at temperature range of 700.about.3000.degree. C. to yield porous carbon fiber paper with high resilience, low porosity, and flexure, and low surface resistance to be used as the substrate of porous carbon electrode in fuel battery.