Abstract: A combustion gas cleaning system includes a transferring portion, a treating portion, an impurity collecting portion, an exhaust portion and a liquid purifying portion. The transferring portion includes a substantially horizontal first duct member having one end communicating with a smokestack. A first sprayer is located around the inside periphery of the first duct member. The treating portion includes an elongated substantially vertical chamber, the top of which communicates with the first duct member. The chamber has a plurality of spaced fan members disposed within the chamber transversely along the length thereof. A second sprayer is disposed adjacent each fan member. The impurity collecting portion includes a second horizontal duct member extending from the lower end of the chamber. A liquid reservoir communicates therewith through a plurality of openings in the bottom of the second duct member. The liquid level in the second duct member reduces the cross-sectional area thereof.