Carbon fiber is a new composite material, excellent in physical properties and chemical properties. Carbon fiber is of tensile strength at 3500MPa or more, 7-9 times that of steel; Tensile elastic modulus of 23000 ~ 43000MPa; Tensile elastic modulus higher than that of steel, and specific gravity is less than a quarter of the steel. With outstanding corrosion resistance, it keeps stable in an organic solvent, acids, bases and etc.