The invention discloses a method for preparing porcelain granules by using fly ash, which comprises the following steps: putting fly ash, potassium feldspar and quartz as raw materials into a ball mill respectively, dry-milling the raw materials, sieving the milled raw materials respectively, removing iron from the sieved fly ash, putting the fly ash after iron removal, the sieved potassium feldspar and quartz and kaolin into the ball mill, and wet-milling and evenly mixing the materials to form mixed slurry; and granulating the mixed slurry by adopting a pressure type spray granulator, putting the granules into an alumina crucible, placing the alumina crucible into a silicon-carbon rod resistance furnace, sintering and naturally cooling the granules, and taking out the granules to obtain the high-strength porcelain granules. The method for preparing the porcelain granules by using the fly ash is not only favorable for saving natural resources and reducing the production cost, but also favorable for environmental protection. The fly ash does not need to be crushed by a high-power crusher, and the fly ash is mixed evenly. The production process is easy to control, and has little energy consumption; the strength of the prepared fly ash porcelain granules can reach 60 to 120MPa; and the porcelain granules have good properties of light weight, high temperature resistance, corrosion resistance and the like, and can be used as a fracturing propping agent for middle and deep layer oil-gas fields.