Bag Filter makes up of frame, ash bucket, in-the-box, on-the-box, bag, frame, jet cleaning devices and plc components such as control procedures. In -the -box is the sub-room structure, while working the gas spread out by the dust collecting duct in all ash bucket. Coarse particles directly fall into the ash bucket bottom for wind speed reducing and the ash bucket spoiler role in the collision, fine dust rose with the bag at all between the fine dust was blocked leaving the outer surface of the bag, cleaning gas clearance role with negative pressure ventilation through the bag into the mains from the body into the atmosphere, reaching the purpose of purification.