NOVELTY - Hollow fiber comprising a hollow positioned at the center of the hollow fiber, macropores positioned adjacent to the hollow, and mesopores and picopores positioned adjacent to macropores, where the picopores are three dimensionally connected to each other to form a three dimensional network structure, comprises a polymer derived from polyamic acid, and the polyamic acid comprises a repeating unit obtained from aromatic diamine including at least one ortho-positioned functional group with respect to an amine group and dianhydride.    USE - The hollow fiber is useful for separating at least one gas comprising helium, hydrogen, nitrogen, methane, oxygen, nitrogen and/or carbon dioxide (claimed).    ADVANTAGE - The hollow fiber has high selectivity, preferably oxygen/nitrogen selectivity of greater than or equal to 4 (preferably 4-20), carbon dioxide/methane selectivity of greater than or equal to 30 (preferably 30-80), hydrogen/nitrogen selectivity of greater than or equal to 30 (preferably 30-80), hydrogen/methane selectivity of greater than or equal to 50 (preferably 50-90), carbon dioxide/nitrogen selectivity of greater than or equal to 20 (preferably 20-50), and helium/nitrogen selectivity of greater than or equal to 40 (preferably 40-120). The hollow fiber exhibits high thermal, chemical and mechanical stability, and high gas permeability.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a dope solution composition for forming a hollow fiber comprising: polyamic acid including a repeating unit prepared from aromatic diamine including at least one ortho-positioned functional group and dianhydride; an organic solvent comprising dimethylsulfoxide, N-methyl-2-pyrrolidone, N,N-dimethyl formamide, N,N-dimethyl acetamide, alcohols comprising methanol, ethanol, 2-methyl-1-butanol or 2-methyl-2-butanol, ketones comprising gamma -butyrolactone, cyclohexanone, 3-hexanone, 3-heptanone, 3-octanone, acetone or methyl ethyl ketone, tetrahydrofuran and/or trichloroethane; and an additive comprising water, alcohols comprising glycerol, ethylene glycol, propylene glycol or diethylene glycol, polymer compounds comprising polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyethylene glycol, polypropylene glycol, chitosan, chitin, dextran or polyvinyl pyrrolidone, and/or salts comprising lithium chloride, sodium chloride, calcium chloride, lithium acetate, sodium sulfate or sodium hydroxide; and    (2) a method of preparing a hollow fiber, comprising spinning the dope solution composition to prepare a polyamic acid hollow fiber; subjecting the polyamic acid hollow fiber to imidization to obtain a polyimide hollow fiber; and heat-treating the polyimide hollow fiber to obtain a hollow fiber including thermally rearranged polymer, where the hollow fiber comprises a hollow positioned at the center of the hollow fiber, macropores positioned adjacent to the hollow, and mesopores and picopores positioned adjacent to macropores, and the picopores are three dimensionally connected to each other to form a three dimensional network structure.