Provided is a method for treating roasting tail gas of a molecular sieve. The method is conducted in equipment comprising a quench tower, an absorption tower and a washing liquid storage tank, and an injection device used for injecting washing liquid is arranged in the quench tower. The method includes the steps that the roasting tail gas of the molecular sieve is made to make first contact with first washing liquid in the quench tower, and the first washing liquid comprises washing liquid from the injection device of the quench tower and washing liquid from the washing liquid storage tank; gas material flow obtained after first contact makes second contact with adsorption packing and second washing liquid from a washing liquid spraying area in a packing layer of the absorption tower; and the first washing liquid obtained after first contact and the second washing liquid obtained after second contact are mixed at the bottom of the absorption tower to be used as the first washing liquid and/or the second washing liquid again. The washing liquid is circulated in two loops in the equipment, and thus while the utilization rate of the washing liquid is increased, waste heat of the roasting tail gas of the molecular sieve can be recovered more effectively, and pollutants contained in the roasting tail gas of the molecular sieve are removed.