Ultra-fine aluminum silicate is synthesized from aluminum sulfate and sodium silicate generally.It consumes aluminum containing chemicals with a high cost.Therefore, a new method that used aluminum bearing waste liquid as raw material was developed. The new method consisted of reaction, polymerization, surface modification, aging,and washing.Besides, the properties of the product were studied with compositional analysis, infrared spectroscopy, SEM, XRD.The results showed that the diameter of primary particles of the product was about 10~40 nm, and the mean diameter was 100nm for the secondary particles.A kind of 3-D network with Si—O and Al—O bonds built up its amorphous non-crystalline structure.The product was up to the current enterprise standard of China.Its chemical formula was Na2O · Al2O 3 ·mSiO 2 ·nH2O(m=9—11, n=4—6).