The invention discloses a flue gas treatment device, comprising a casing, and the casing is provided with a gas inlet end and a gas outlet end; the interior of the casing is further provided with a heat exchange module, and the heat exchange module comprises a plurality of heat exchange tubes. A cooling medium is introduced into each of the heat exchange tubes, and at least one water guiding member is disposed on the surface of each of the heat exchange tubes. According to the flue gas treatment device provided by the invention, the heat exchange module of the device can exchange heat with moisture-containing flue gas, so that the temperature of the moisture-containing flue gas can be rapidly decreased, water vapor can be condensed and condensed water flow along the heat exchange tubes toreduce the moisture content of the flue gas. The surfaces of the heat exchange tubes are further provided with the water guiding members, and the water guiding members can timely enable liquid films deposited on the surfaces of the heat exchange tubes through condensation precipitation to be away from the surfaces of the heat exchange tubes, thereby avoiding overthick liquid films deposited at thesurfaces of the lower portions of overlong heat exchange tubes and avoiding the problems of too large thermal resistance and too low heat exchange efficiency, and therefore the condensation and removal effect of water vapor in the flue gas can be ensured to a greater extent.