The invention relates to a device and a method for jointly and cooperatively removing various pollutants of fume in coal-fired boiler. The device comprises a boiler (1), an air preheater (2) and a dust remover (3) which are communicated in sequence as well as a wet electric dust remover (5) provided with a dust collecting electrode and an electrode and communicated with the dust remover (3) through a flue, a chimney (6) communicated with the wet electric dust remover (5) and an injecting device for cooling the cooling device of the flue and injecting ionic liquid (L) for the wet electric dustremover (5), wherein the welt fume input end of the wet electric dust remover (5) is connected with the dust remover fume output end of the dust remover (3), and the wet fume output end of the wet electric dust remover (5) is connected with the chimney fume input end of the chimney (6); and the ionic liquid output end of the injecting device is connected with the wet ionic liquid inlet end of thewet electric dust remover (5). The device can greatly simplify the process flow and reduce the investment and operation cost.