Abstract: A fly ash-based fire-prevention and extinguishing material with carbon dioxide mineralized and stored, and a preparation method thereof are provided. The preparation method includes: separately weighing 100 parts to 120 parts of water, 1 part to 3 parts of a solid strong alkali, and 20 parts to 40 parts of a fly ash as raw materials, pouring the raw materials into a reactor successively to obtain a resulting mixture, and stirring the resulting mixture at a high rotational speed; adding 10 parts to 20 parts of a solubilizing agent to the reactor, sealing the reactor, introducing carbon dioxide to the reactor at room temperature to maintain a carbon dioxide pressure to obtain a resulting slurry, and stirring the resulting slurry at a high rotational speed; and further introducing carbon dioxide into the reactor to increase the carbon dioxide pressure, and stirring the resulting slurry at a low rotational speed.