The invention discloses attapulgite nutritional soil and a preparation method thereof. The attapulgite nutritional soil is prepared from, by weight percentage, 15-35% of acidized attapulgite, 25-55% of acidized sludge, 2-15% of high-viscosity attapulgite clay, 2-15% of crushed stone attapulgite flower ceramsite soaked by biogas slurry, 2-15% of smashed peat, 2-15% of biogas residues, 1-10% of smashed plant fiber, 0.5-5% of expanded vermiculite, 0.5-5% of expanded perlite and 0.1-5% of high-water-absorption resin. The attapulgite nutritional soil is prepared with attapulgite as the main raw material, contains a large quantity of organic substances and various microelements, facilitates normal growth and development of plants, and is good-quality nutritional soil which is comprehensive in nutrient, high in fertilizer efficiency, free of toxin, bacteria, harm and odor and good in water retention capacity. Various wastes are used in the raw materials, the resource utilization rate is increased, the nutritional soil is environmentally friendly and saves energy, production cost is reduced, and economic benefits are improved.