The invention discloses a method for effectively utilizing metatitanic acid washing filtrate. The method comprises the following steps: firstly, introducing crystalline slurry into a disc filter through a feeding pipe after a disc runs normally and respectively introducing the metatitanic acid washing filtrate into two sides of the feeding pipe; secondly, respectively introducing the metatitanic acid washing filtrate into a first washing area, a second washing area and a third washing area of the disc for washing; thirdly, returning the washing filtrate from the second washing area and the third washing area to an acidolysis working section to serve as extracting water. According to the method disclosed by the invention, acid wastewater washed by the metatitanic acid is applied to dilutedwater filtered by the disc and the washing water from the first washing area, the second washing area and the third washing area, so that early hydrolysis of titanium liquid and great dissolved quantity of ferrous sulfate are avoided when the dilute water is added; in addition, the early hydrolysis of the titanium liquid when first-time washing, second-time washing and third-time washing are carried out, and further the amount of the ferrous sulfate dissolved by three-time washing is reduced.