The invention specifically relates to a method for recycling phosphoric acid from tail gas produced in carbonization and activation of active carbon in a phosphoric acid process, which belongs to the field of recycling of acids from tail gas of active carbon. The invention enables high efficiency and low cost in recovery of phosphoric acid from tail gas to be achieved and has substantial economic benefits and wide applicability. According to the method, tail gas containing phosphoric acid is recovered, uniformly mixed with an active carbon raw material and then subjected to drying, which enables tail gas recovery phosphoric acid liquid to adsorb on the active carbon raw material, and the obtained active carbon raw material is used as a raw material for active carbon prepared by using the phosphoric acid process. According to the invention, based on the porosity of the active carbon raw material, the raw material is used as a carrier of low concentration recovered acid for adsorption of phosphoric acid, thereby enabling the problem of difficult filtration of recovered liquid to be overcome; through drying of the active carbon raw material which has adsorbed the recovered liquid, the problem of difficult evaporative concentration of the recovered liquid is overcome, the concentration of phosphoric acid increases in the process of drying at the same time, and therefore, etching of phosphoric acid on carbon-containing substances is improved and quality of active carbon prepared in the phosphoric acid process is enhanced. The method has the advantages of simple operation, easy industrial popularization, low production cost and remarkable economic benefits.