The invention relates to a preparation method of a covalent cross-linking polybenzimidazole high-temperature proton exchange membrane. The preparation method comprises the following steps: carrying out covalent cross-linking by taking polybenzimidazole resin as a raw material and taking bivariate or multivariate halides and epoxy compounds as cross-linking agents, and forming the membrane through a solvent volatilization method. The covalent cross-linking polybenzimidazole high-temperature proton exchange membrane prepared by utilizing the method disclosed by the invention has the advantages of better dimensional stability, thermodynamic stability and chemical stability, high phosphoric acid doping level and higher proton conducting property and can be used within a range of 20-200 DEG C. The preparation process disclosed by the invention is simple and low in raw material cost; and the prepared cross-linking proton exchange membrane has potential of being applied to a high-temperature fuel cell.