The invention belongs to the technical field of precious metal catalysts, particularly relates to modified ultrafine carbon black with high activity and high stability, preparation of the modified ultrafine carbon black and an application of the modified ultrafine carbon black as a carrier of a palladium-carbon catalyst, and further relates to an application of the catalyst in a hydrogenation reduction reaction of nitrobenzene and derivatives of the nitrobenzene. A particle size of the modified ultrafine carbon black is 5-100 nm, a specific surface area of mesopores larger than 4 nm accounts for 85% or more of a total specific surface area, and a pore channel size is 5-15 nm. According to the preparation method, ultrafine carbon black is modified, an active metal and the carrier for preparing the catalyst are dispersed in a ''mutual inlay'' manner to prevent the agglomeration of the metal particles during the reaction, and the developed mesoporous channel structure is favorable for thediffusion of reaction molecules and avoiding aggregation of organic macromolecules such as reaction intermediates to cover the active sites of the catalyst and block the pore channels; and the prepared catalyst has high activity and long service life.