Titanium dioxide (TiO2) nanopowders were successfully prepared by thermal processing of the precursor of titanium hydroxide, urea and sodium acid carbonate (NaHCO3). The products were characterized by Xray diffractometry, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The results show that NaHCO3 has a certain effect on the average crystallite size and dispersity of TiO2 nanopowders, at the same time other phases (Na2SO4 and Na2CO3) will be introduced. However, Na2SO4 has distinctive intercalation ability and catalytic activity. TiO2 (anatase) powders can be prepared at -600 degrees C for 2 h with addition of 2-10 wt% NaHCO3, and the average crystallite size is 20.0-22.3 nm. The surface of the sample mainly consists of Ti, O, C, Na and S five species elements. (C) 2009 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.