The invention discloses a method for producing a foamed ceramic building insulation material by using lithium tailings and steel slag tailings. The method comprises the following steps: preparing thelithium tailings, the steel slag tailings, a clay raw material, a foaming material A and water according to a certain ratio, mixing, grinding, then sieving, removing iron, putting into a mud pit, performing pressure filtration to obtain a mud cake, then refining mud, adding a foaming material B, namley polystyrene particles, in the mud refining process, performing extrusion moulding on a mud section extruded in the mud refining process to obtain a foamed ceramic wet blank, sending the wet blank into a tunnel kiln for drying, and then firing in an energy-saving double-layer tunnel kiln at hightemperature of 1100-1200 DEG C according to a certain firing system to obtain a blank brick, and processing and cutting to obtain a finished product. The preparation method is simple; the prepared foamed ceramic is good in regularity, high in strength, anti-aging, fire-proof, flame-retardant (A1 grade), water-proof, excellent in insulation performance, eco-friendly (non-toxic, harmless and radiation-free) and convenient and efficient to construct, can be used as a building exterior wall insulation material and a chimney flue corrosion preventing material, and can also be used as a fabricated partition wall material and a self-insulating wall material.