The invention relates to an acid mist purification tower used for waste gas treatment and convenient for energy conservation. The tower comprises a tower body, a liquid supply mechanism, an exhaust pipe, a gas inlet pipe and a purification mechanism, the purification mechanism comprises a packing layer, a sealing ring and a dehydration assembly, the dehydration assembly comprises a screw rod, a threaded pipe and a driving unit, the liquid supply mechanism comprises a water tank, a material tank, a water pump and a spraying pipe, a partition plate and a baffle are arranged in the water tank, and a liquid supply assembly is arranged on the side, away from the baffle, of the partition plate. According to the acid mist purification tower used for waste gas treatment and convenient for energy conservation, alkali liquor can be discontinuously supplied to the packing layer through the liquid supply mechanism, an aqueous solution falling from the packing layer can be recycled and mixed with an alkali material in the material tank to prepare an alkali liquor, and in the purification mechanism, water in the packing layer is conveniently thrown out through the dehydration assembly, so that the alkalinity of the solution in the packing layer is ensured, the contact reaction with a large amount of acid mist is facilitated, the flowing frequency of the alkali liquor is reduced, the equipment energy consumption is reduced, and energy conservation is realized.