The invention discloses sepiolite molding sand. The sepiolite molding sand is prepared from the following raw materials in parts by weight: 100-120 parts of reused sand, 250-260 parts of sepiolite, 2-3 parts of diisobutyl phthalate, 20-30 parts of pulverized coal, 1-2 parts of vaseline, 3-5 parts of sodium carbonate, 13-18 parts of petroleum sodium silicate, 10-14 parts of phenolic resin, 2-4 parts of benzenesulfonic acid and a proper amount of water. The preparation method of the sepiolite molding sand comprises the following steps: calcining sepiolite serving as the main raw material, adding the diisobutyl phthalate and the like, dispersing, grinding, and calcining at a high temperature; due to addition of binding agents such as the petroleum sodium silicate, the sepiolite molding sand has excellent air permeability, toughness, plasticity, wet caking property, high-temperature collapsibility and small shrinkage factor; and meanwhile, the reused sand is used, so that the cost is reduced. The sepiolite molding sand has the advantages of preventing sand from being attached to castings, avoiding peeling, ensuring the accurate size and the bright and clean surfaces of the casting, having the high rate of finished products, being environment-friendly and increasing the economic benefits.