The nanometer TiO2 was prepared by pyrohydrolysis with titanic solution. The effects of species and content of the surfactants on the particle size, morphology and phase of TiO2 were studied by using LPA, XRD and TEM respectively. The results show that it is beneficial to reducing the aggregation of TiO2 particles with adding surfactants to the solution. Nanometer TiO2 powders with the size of 40-55 nm are obtained by adding the anion surfactants in the optimal content of 1.5% (mass fraction). The effect of cationic surfactant for reducing particle aggregation is not as good as that of anion. The crystal phase constitutent of TiO2 is dependent on the temperature of thermal treatment and complete anatase can be achieved after calcining in the temperature range of 350-750 ℃.