The invention discloses a device for simultaneously treating flue gas and organic waste water. The device comprises a treatment tower, wherein an air pipe is arranged in the center of the treatment tower; flue gas is introduced into the tower and overflows from a bell mouth at the bottom end of the air pipe; a water inlet is formed in the lower end of the treatment tower for introducing waste water; a water outlet is formed in the upper end of the treatment tower; the water outlet is connected with an anaerobic bioreactor; an air outlet is formed in the top end of the treatment tower; a sewageoutlet is formed in the bottom end of the treatment tower; three layers of perforated partition plates are arranged inside the treatment tower from bottom to top; and a manganese dioxide granular layer, a manganese dioxide granular layer and a limestone granular layer are respectively piled on the lower, middle and upper partition plates. Contaminants in the flue gas contact with the waste waterin the treatment tower, and react with manganese dioxide and limestone in turn, and organic pollutants are degraded in the waste water at the same time, and thus simultaneous treatment of the flue gasand the organic waste water is realized, the treatment efficiency is high, equipment is simplified, and the cost is saved, so that the device is suitable for popularization and application.