The invention provides a regeneration process method for a deactivated gas denitration catalyst. The regeneration process method comprises the following steps: pretreating a deactivated gas denitration catalyst, performing in-situ preparation of a TiO2 porous film on the surface of the catalyst, and carrying nanoparticles, thereby obtaining a regenerated gas denitration catalyst which is good in denitration property and wide in active temperature window. Since the temperature range of a regenerated catalyst is widened through the high specific surface area of a porous material and high catalysis activity of a nano material of the porous material, the denitration efficiency is improved, meanwhile the problems that a denitration catalyst is high in regeneration cost, complex in process, andthe like when a conventional regeneration process is used, are solved, and thus the method has good market prospects.