The invention relates to the field of industrial aluminum electrolysis, in particular to a method for collecting gas during the overhaul of an electrolytic cell, which is suitable for reducing the unorganized emission of the electrolytic cell during the overhaul process. A gas collecting device is additionally arranged on the electrolytic tank, and an independent flue gas purification system is additionally arranged near an overhaul tank of an electrolytic workshop, and when the electrolytic cell is overhauled, the smoke generated during the groove planing process is collected through the gascollection device, then is purified through the smoke purification system and is discharged into the atmosphere. The method provided by the invention can greatly reduce the unorganized discharge amount during the overhaul process of the electrolytic cell, can collect and treat the pollutants, such as dust in the groove planing process, etc., and does not introduce an original purification system.The method does not influence the normal slot planing work of the electrolytic cell, meets the requirements of the working space, and adapts to the operation and environment of the electrolytic cell.