The crystal-form-control I able nanosize TiO2 was obtained using homogeneous hydrolysis method by the addition of toluene-p-sulfonic acid (TSA). Two Processes of the rutile phase formation were proposed. The sample with 0.2 mole ratio of toluene-p-sulfonic acid was a mixed crystal of anatase and rutile, and characterised that the size of nano-crystal line was 19.5 run for rutile. and 13.5 nm for anatase, the specific surface area was 72.7 m(2)/g, and the energy of band gap was 2.83 eV. The mechanism of development of rutile nanosize TiO2 was presented in homogeneous hydrolysis system with TSA.