An attapulgite flue gas desulfurizer is prepared from the following raw materials by weight: 100-120 parts of attapulgite, 40-45 parts of active carbon, 20-24 parts of magnesium chloride, 4-5 parts of zinc oxide, 25-28 parts of calcium oxide, 6-8 parts of sodium carbonate. 20-24 parts of wild chrysanthemum flowers, 10-12 parts of cordate houttuynia, 35-40 parts of monazite powder, 5-7 parts of sodium metasilicate, 3-4 parts of coconut fatty acid monoethanolamide, 4-5 parts of auxiliary agents, and a proper amount of water. By using attapulgite and monazite powder, the desulfurizer of the invention has adsorption decoloration and ion exchange effects, has good adsorption effect on sulfur dioxide, decreases the using amount of active carbon, and reduces the cost; by using wild chrysanthemum flowers and cordate houttuynia, the desulfurizer of the invention not only has adsorption effect, but also has antibacterial effect after carbonization; by using a plurality of basic metal oxides, rapid desulfurization is realized; the desulfurizer of the invention is high in porosity, large in adsorption quantity, easy to regenerate, and simple in production process, and can greatly reduce the operation cost of dry-method desulfurization.