A fluorocarbon resin composition is applicable to produce high-frequency circuit boards including a polytetrafluoroethylene resin; a fluorine-containing copolymer such as poly fluoroalkoxy and fluorinated ethylene propylene; low molecular-weight PTFE micro-powders and inorganic powders; in particular the temperature of pressing copper foil substrates is lowered from 350° C. to 250° C. via a lowering temperature rate of 1 to 4° C./min to improve the crystallinity of the fluorocarbon resin composition as well as improve the copper foil substrate with a high thermal conductivity and a wide range of dielectric constant.