The invention discloses a high-electric conductivity aromatic polymer ionic liquid diaphragm material and a preparation method thereof. The high-conductivity aromatic polymer ionic liquid diaphragm material comprises an cation and an anion, wherein the cation is a composite cation formed by combining at least one ion of hydrogen ions or metal ions with organic molecules; and the anion is a fluorine-contained sulfonic acid anion or a fluorine-contained sulfimide anion which is connected to an aromatic benzene ring-contained polymer side chain. Compared with the prior art, the polymer ionic liquid diaphragm material of the invention has the advantages of difficult loss of ionic liquid, electric conductivity without depending on water, penetration resistance of OH-anion, methanol or vanadium ions, and the like, can form a stable ion channel which has high ionic activity, high chemical stability, low ion activating energy and easy adsorption of organic polar solvents and is an ideal diaphragm material which can be applied to various fields of lithium ion batteries, secondary lithium ion batteries, methanol fuel batteries, liquid flow batteries, electrodialysis water treatment, atomic energy industry and analysis, catalytic synthesis, chlor-alkali industry, and the like.