In this research

a novel method of ionic exchange-hydrolysis was applied to prepare TiO

2

nanoparticles with uniform small size（20 nm）.First

TiO

2

sol was prepared by removing chloride ion in TiCl

4

solution using anion-exchange resin

and then it was dried and calcined to obtain crystalline nano-TiO

2

.The results show that the chloride ions can be removed efficiently by this simple dechlorination method and the preparation period was short.The effects of solvent

removal extent of chloride ion

drying method and calcination temperature on the photocatalytic activity of nano-TiO

2

product were investigated by photocatalytic degradation experiment of AO7 dye

and the optimal preparation condition was finnally found.