The invention relates to a purification system, in particular to an electrolytic flue gas dry purification system. The system comprises a dust remover, a dust remover outlet pipe, a reactor and a collecting pipe, wherein the dust remover outlet pipe is arranged on the top of the dust remover; the reactor is connected with the dust remover; the collecting pipe is connected with the reactor; the bottom of the dust remover is communicated with a fluorine-carrying alumina storage cabin; the reactor is communicated with a fresh alumina storage cabin; and the dust remover outlet pipe is communicated with a chimney through a main induced draft. The system has the advantages that: local resistance is reduced by varying a pipe configuration mode so as to reduce entire on-way resistance of the purification system and save energy consumption; and the system improves purification effect and has the advantages of small occupied area, high purification efficiency, low energy consumption, small maintenance capacity, high control degree and the like.