The invention discloses a process for precipitating sewage in an ardealite slag field for sodium fluosilicate production. The process comprises the following steps: S1, conveying ardealite slag slurry generated in phosphoric acid production to the ardealite slag field for stockpiling; s2, in the stockpiling process, the ardealite slag slurry naturally settles under the action of gravity for liquid-solid separation; s3, collecting a liquid phase into a water return pool; s4, returning to a sodium fluosilicate production device for sodium fluosilicate production; s5, after the sewage is naturally settled, the settled sewage in the ardealite slag field is conveyed into a sodium fluosilicate production device, the sewage generated by the sodium fluosilicate production device is returned to the phosphoric acid production device again, and finally water balance is formed. According to the process for precipitating sewage in the ardealite slag field for sodium fluosilicate production, any natural water such as fresh process water and the like is completely replaced and no longer used, qualified recycled water is treated, water is saved, industrial wastewater is reduced, the water storage pressure of the slag field is relieved, water balance in the whole process is adjusted, and the current production and environmental protection requirements are met.