The invention discloses a method for preparing a fluoro-chlorine exchange catalyst with high specific surface area. The method comprises the following steps: carbonizing a metal-organic framework material MIL-101 (Cr) serving as a raw material and metal brine serving as an assistant, and performing fluoridation treatment, thereby obtaining the fluoro-chlorine exchange catalyst with high specific surface area. The method disclosed by the invention has the advantages that the metal-organic framework material MIL-101 (Cr) with high specific surface area, high internal pore volume and uniform andordered Cr element distribution serves as the raw material of the fluoro-chlorine exchange catalyst, so that the prepared fluoro-chlorine exchange catalyst also has the characteristics of high specific surface area, high internal pore volume and uniform and ordered Cr element distribution; the assistants are added by an adsorption method, so that the distribution of the assistants is uniform, andthe effective utilization rate of the assistants is improved; and the product has the characteristics of high specific surface area, rich internal pores, high catalytic activity, uniform assistant distribution and the like, and is applicable to the fluoro-chlorine exchange reaction.