The invention provides a method for preparing porous materials with rare earth tailings. The method is characterized by mixing the rare earth tailings with cement in a mass ratio of (2-4):(8-6), adding lithium carbonate, starch and potassium permanganate, adding H2O2 after stirring the materials and curing the product for 20-30 hours under the condition of standing. The method has the beneficial effects that comprehensively considering the characteristics of the chemical components of the rare earth tailings, the rare earth tailings replace part of cement, the basic raw materials are debugged by adding the additive, the ratio of the raw materials to the additive to an activator to a foaming agent is adjusted and each link in the preparation process is strictly controlled, so that the foaming speed is matched with the matrix setting time, thus preparing the rare earth containing porous materials which have pore diameters less than 1mm, are uniform in bubble distribution and have low density and high strength; the method is short in process flow, simple in equipment and easy to operate and can take full advantage of the industrial solid wastes, namely the rare earth tailings; the obtained products have wide ranges of application, high added values and the environmental protection function.