The invention provides a wet-method three-stage smoke elimination, dust removal and gas purification device for purifying combustion smoke gas and organic waste gas with a double-alkali method, a sodium-alkaline method, a magnesium method, an ammonia method, a waste alkaline liquid method, a sea water method, and the like. The device comprises a main tower and an inner tower, wherein, the main tower is provided with a gas purification outlet pipe, a waste gas inlet pipe, an outlet pipe for ash water and ash slag, and a medicine liquid spraying pipe; the inner tower is provided with a top plate and a central duct, and is coaxial arranged with the main tower. The device is characterized in that a baffle plate for dividing the circular ring cylindrical space between the two towers into an upper space and a lower space which are not communicated with each other is fixedly connected between the main tower and the inner tower; the upper space is provided with a water outlet; the wall of the inner tower is provided with a tangential inlet and a tangential outlet; waste gas enters the central duct from the lower space through the tangential inlet and enters the upper space from the central duct through the tangential outlet; the side wall of the main tower is provided with a flush hole which can be used for removing ash in the tangential inlet and the tangential outlet. Therefore, the device can effectively eliminate smoke and remove fluorine, nitre, nitrogen and organic waste gas. The Ringelmann blackness of the smoke is less than or equal to grade one, the dust removal rate is more than or equal to 99.99 percent, the dust discharging concentration is less than or equal to 30mg / m<3>, and the desulfurization degree is more than or equal to 99 percent. Besides, the invention ensures continuous and efficient purification and lowers the cost of the towers and the device.