Bag dust filter is a kind of high efficient dust removal equipment, dust removal with high efficiency, stable running, simple operation and maintenance etc, are widely used in steel, non-ferrous metallurgy, building materials, chemical industry, food, etc, in foreign countries is also widely used in power plant coal-fired boiler flue gas purification mainly adopts electrostatic precipitator, in part, small boiler adopts Gao Xiaowen venturi + water membrane dust collector. As the requirement of environmental protection increasing, bag filter is applied again in silence after decades to coal-fired boiler flue gas.