The invention discloses a mineral high-strength high-water compound gel fire preventing and extinguishing material and a preparation method thereof. The method comprises the following steps: weighing the following components in parts by weight: 10-20 parts of sulfoaluminate cement clinker, 2-3 parts of lime, 4-5 parts of water glass and 200-250 parts of water; mixing the sulfoaluminate cement clinker with water, and sufficiently stirring; mixing the water glass with water, and sufficiently stirring; sufficiently mixing the two kinds of slurry after uniform stirring, and continuously stirring; stirring at a speed of 60-90 revolutions per minute for 3-5 minutes; and adding lime to keep on stirring for 3-5 minutes. The mineral high-strength high-water compound gel fire preventing and extinguishing material has the advantages of low cost, high strength, high viscosity, good stability, wide application, no toxicity and no hazard.