Abstract: The morphology and mechanism of rutile titanium dioxide coated by aluminum oxide were investigated and the effects of pH and reaction temperature were studied experimentally. The results indicate that the dispersions of titanium dioxide powder possesses a highest Zeta potential when pH closed to 10, and at this condition titanium dioxide powder is able to be dispersed best in water. Uniform thin film is formed on titanium dioxide particles at high reaction time and temperature, and also when CH 2OHCH 2Cl is used instead of H 2SO 4. The white value increases with the increase of the reaction temperature and time.