Modified clay and preparation method thereof

The invention relates to a modified clay and a preparation method thereof. The modified clay is prepared by being roasted at 800-1100 DEG C for 0.3-10h, comprising the following materials by mass percentage: 0.1-3.0 of P, 0.1-4.0 of RE2O3 and 0.1-1.5 of Na2O; the pore volume of the modified clay is 0.1-0.5ML/g, the specific surface is 50-400m /g, and the average grain diameter is 0.5-15[mu]m. The preparation method comprises the following steps: roasting clay at 800-1100 DEG C for 0.3-10h, mixing the roasted clay and deionized water evenly, adding inorganic alkali solution with 0.5-15 mol/L of OH-concentration in the mixture to react at 50-100 DEG C for 0.1-5h and obtaining clay slurry, wherein, the mass ratio of deionized water to clay (counts with dry basis) is 1.5-10, the mass ratio of inorganic alkali solution to clay (counts with dry basis) is 0.5-8, and the inorganic alkali is selected out of one or more of sodium hydroxide, water glass, ammonia and sodium meta-aluminate; filtering the clay slurry, washing the obtained clay slurry by inorganic acid solution at 30-100 DEG C, introducing phosphorus and rare earth in the manner of soaking, then filtering and drying to obtain the modified clay.