TiO 2 nanoparticles have been prepared using sol-gel method from titanium(IV), isopropoxide, isopropyl alcohol, ammonia hydroxide as precursors at mild condition without any post heat treatment for crystallization. The nanocrystalline TiO 2 powders were composed of rutile form TiO 2 by X-ray diffraction. The size of nanoparticles was examined by transmission electron microscopy and is about 10-15 nm, and the Brunauer-Emmett-Teller specific surface area of the rutile nanopowder makes up 159.6 m 2 /g. Photochemical degradation of phenol solution under ultraviolet irradiation of the synthesized TiO 2 nanoparticles has been carried out.