Abstract: Using industrial condensed titanyl sulfate solution as raw material，Rutile titanium dioxide was prepared by hydr olysis process within adding external seeds.The influences of composition of titanyl sulfate solution and operation conditions on the tintreducing power of rutile titanium dioxide were studied.The experimental results showed that the Tcs and Scx of titanium dioxide increased first and then decreased with the increase of seed addition and delay time of grey point judgment; and increased slightly and then decreased with the increase of F value，and increased with the increase of titanium dioxide concentration.The F value of titanium solution（the mass concentration ratio of free sulfuric acid+sulfuric acid combined with Ti to TiO2） was about 1.90，the ratio of Fe/TiO2 （the mass concentration ratio of Fe to titanium dioixde） was less than 0.5，the mass concentration of TiO2 was 190~200 g/L，the dosage of seeds（the mass ratio of titanium dioxide in crystal seed to the titanium dioxide in related industrial condensed titanyl sulfate solution） was controlled at 2.0%~2.2%，the grey point was “base point + 20 min”，the aging time was 0~30 min，and the diluted water was added at the time of 100 min after the second boiling.Under these conditions，the rutile titanium dioxide obtained by the processes of primary washing，bleaching，secon dary washing，salt treatment and calcination has better tintreducing power.

Key words: titanyl sulfate solution hydrolysis process；rutile titanium dioxide；tintreducing power