The present invention discloses a method of separating C8 aromatic hydrocarbon isomers. The anion-pillared metal-organic framework materials with a pore diameter of 5-10 Å is used as adsorbents to achieve selective adsorption and separation of C8 aromatic hydrocarbon isomers by contacting the C8 aromatic hydrocarbon isomers with the adsorbents; the anion-pillared microporous materials are porous materials formed by metal ion M, inorganic anion A and organic ligand L through coordination bonds, with the general formula of [MAL2]n, where n>4 and n is an integer; the descried “metal ion M” is Fe2+, Co2+, Ni2+, Cu2+; the descried “inorganic anion A” is SiF62−, NbOF52−, TaF72−, ZrF62−, TiF62−, GeF62−, SO3CF3−, NbF6−; the descried “organic ligand L” is selected from any of the following: