TiO 2 nano powders were prepared by means of microwave radiation using the collosol of titanium dioxide hydrate made from sponge titanium. TEM analysis indicates that the morphology of the nano particles is spherical, and the particle size is in the range of 60 nm~100 nm. The distribution of the particle size is fine. The Zeta potential value of the sample in water is +48 7 mV, indicaling good dispersivity. The transformation temperature of the nano crystal is much lower than that of the common crystal. The starting material is cheaper, and using this method nano particle size is easily controlled in production.