The invention relates to a method for solving large pressure difference of an iron-molybdenum catalyst in an iron-molybdenum converter, relates to a method for regenerating the iron-molybdenum catalyst, and is used for solving the problem that the stop treatment needs to be carried out and the treatment speed is low when the pressure difference of the existing iron-molybdenum catalyst is large. According to the method, an iron-molybdenum converting system comprises a heating furnace, the iron-molybdenum converter, a first coke oven gas pipe, a second coke oven gas pipe, a fuel gas pipe and an escape pipe; after coke oven gas is fed in the heating furnace and is heated to 400 DEG C, the coke oven gas is mixed with the coke oven gas in the normally running iron-molybdenum converter together to be fed in the iron-molybdenum converter, so that an iron-molybdenum bed is heated till the hot-spot temperature of the bed is 450-500 DEG C; impurities such as coil tar oil and benzene adhered on the surface of the iron-molybdenum catalyst are melted and move downwards, so that the pressure difference of the catalyst bed is reduced, and then the temperature of the iron-molybdenum catalyst bed is reduced to the level of normal production. The method is performed under the condition that facilities such as equipment, pipelines and valves of a fine desulfurization system are not changed, and the pressure difference of the iron-molybdenum catalyst is reduced without stopping production.