The invention provides an enhanced geopolymer and a preparation method thereof. The preparation method comprises the following steps: preparing the following raw materials: phosphate and/or polyphosphates, meta-kaolin, fly ash, sodium silicate, an alkaline compound, silicon dioxide, and water, mixing the raw materials according to a certain ratio, grinding the mixed raw materials to obtain uniform slurry, injecting the slurry into a mould, and carrying out maintenance at a room temperature or low temperature (20 to 80 DEG C) to obtain the geopolymer. The geopolymer, which is produced by the provided formula and preparation method, has the advantages of high temperature resistant and chemical product resistant properties, and excellent mechanical properties, the compressive strength can reach 150 MPa or more, and the application requirements of construction material and high temperature coating can be met. Compared with the conventional construction material production technologies, the provided preparation method has the advantages of simple technology, energy saving, environment-friendliness, low cost, and easy operation.