The invention discloses a method for preparing 4,5-dibromo imidazole and belongs to the field of fine chemical product preparation. The method for preparing 4,5-dibromo imidazole comprises a step of enabling 2,4,5-tribromo imidazole to react with triphenylphosphine, so as to generate 4,5-dibromo imidazole. By adopting the method, triphenylphosphine is adopted as a reducing agent for reducing 2,4,5-tribromo imidazole into 4,5-dibromo imidazole. By adopting the method, 2,4,5-tribromo imidazole can be directly reduced into 4,5-dibromo imidazole at one step, reaction steps are reduced, meanwhile wastes are reduced, the production cost is reduced, and the environmental pollution is reduced.