The invention discloses a long side chain type fluorine-containing sulfonated polyarylether compound based on bisphenol A and a preparation method thereof. The preparation method comprises the following steps: selecting 2,2'-diallyl bisphenol A, bisphenol A and decafluorobiphenyl of different proportions to perform condensation polymerization to prepare a series of polyarylether compounds containing allyl and fluorine atoms; enabling the polyarylether compounds and excessive 3-sulfydryl-1-sodium propanesulfonate to perform addition reaction; and introducing a sulfo group at allyl to finally prepare the long side chain type fluorine-containing sulfonated polyarylether compound based on bisphenol A, wherein the long side chain type fluorine-containing sulfonated polyarylether compound has different ion contents. The compound has a stable fluorine-containing aromatic main chain and a soft sulfonating side chain, can be cast into a membrane through a solution; and the obtained proton exchange membrane has the advantages of an excellent proton conduction rate, oxidization stability, mechanical performances, thermal stability and the like.