The invention relates to a preparation method of porous perfluorinated sulfonic acid resin for catalysts, wherein the preparation method comprises that perfluoro(sulfonyl vinyl)ether and tetrafluoroethylene are polymerized under the condition of co-existence of a solvent, a pore-forming agent and an initiating agent to obtain the product, the perfluorinated sulfonic acid resin having low equivalent weight and low molecular weight is used as the pore-forming agent, the solvent is recycled by a way of adding deionized water and a dispersant and carrying out distillation, at the same time, the resin is molded, after further drying, a granular material is obtained, and moreover, a mixture of one or more of perfluorinated hydrocarbon / perfluorinated cyclic ether / chlorofluorocarbon are used as an extraction agent for extracting the pore-forming agent so as to form a porous structure. The method has simple operating conditions, has no need for high temperature and high pressure, and solves the problem in the prior art that effective catalytic component loss is difficult to overcome during a using process, and the service life of the catalyst is increased; and at the same time, due to the existence of the porous structure, the specific surface area is increased, and the active component utilization rate is improved.