The invention discloses a method for preparing white carbon black from fluorine-containing silica gel. The method comprises the following steps that: in a dissolution kettle with a stirring device and a heating device, the fluorine-containing silica gel reacts with an ammonium fluoride solution to form an ammonium fluosilicate solution; white carbon black is precipitated in the ammonium fluosilicate solution in three stages by use of ammonia gas; generated white carbon black slurry is driven into an aging groove, aged, filtered and subjected to countercurrent washing six times; clear water isused for the sixth washing; partial ammonium fluoride solution is separated from filtrate and is used for recovering ammonium fluoride; the remaining filtrate and a washing liquid are returned to a system to dissolve fluorine-containing silica gel; and white carbon black is obtained by drying filter cakes. The method has the advantages of high rate of utilizing fluorine-containing silica gel, simple process flow, less equipment, convenient operation, low production cost and easy realization of industrial production.