An aluminum oxide production self-owned power plant boiler smoke desulfuration method relates to a method for removing sulphur in coal fired flue gas by a double alkali method and is characterized in that (1) in the desulfuration process, red mud backwater in the aluminum oxide production process is adopted for circulation absorption fluid preparation and circulation absorption fluid supplementary alkaline adjustment; (2) lime dust which is generated in the aluminum oxide production process and lime production, storage and transportation process and intensively recycled by a high-tension static dust catcher to prepare lime mortar which reacts with absorbed alkali liquor in a reaction tank to carry out calcium sulfite captured sulfur and alkali replacement reaction; (3) the calcium sulfite captured sulfur and the alkali replacement reaction are sent into a sedimentation basin for sediment; sediment separated from bottom current enters into an oxidization pond, is added with air for oxidation and dehydrated, and finally desulphurizing slag is discharged; separated liquid supernatant returns to carry out the circulation absorption fluid preparation. The method has reasonable technology, good real operational effect, deals with waste by waste, recycles the waste, and has low desulfuration cost and high desulfuration efficiency.