The invention relates to a non-stop ash cleaning device for a flue of a flat glass melting furnace. The non-stop ash cleaning device comprises the flue (1) and is characterized in that at least one ash collecting tank (2) is arranged below the flue (1), is in matching connection with a bottom opening (1a) of the flue (1) and is in vertical communication with the flue (1). Gate plates (3) are respectively arranged on the ash collecting tank (2) at the two sides of the flue (1) and are in matching connection with gate plate grooves (4) in the ash collecting tank (2). The non-shutdown ash cleaning device has the advantages that the service performance of the flue is improved, and the ash cleaning for the flue can be realized without production stop; and the operation is simple and convenient, and the cost of enterprises is saved during long-term production.