The invention relates to a hydrolyzation method for preparing titanium white, and aims to solve the problem of the wide distribution of the grain diameters of the titanium white produced with the prior art. The method is characterized in that the seed crystal titanium liquid and the hydrolyzing liquid are added step by step, and the autogenetic seed crystals are matured step by step, so that the stability, the uniformity and the dispersivity in the titanium are better. By the method, the titanium white product with controllable and narrow distribution of grain diameters can be obtained. The technical proposal adopted is as follows: the paint-grade titanium white product with the half peak breadth of 80 to 100nm can be obtained by controlling the reaction conditions and the technical parameters such as the method of adding the titanium liquid, the quantity of bottom water, the quantity of seed crystals, the time for maturing the seed crystals, the feeding speed, the concentration of thetitanium liquid, etc. Furthermore, the method needs no further production equipment. Therefore, compared with the prior industrial hydrolyzing technology, the method has the advantages of strong adaptability, high product quality, etc.