This research revisited the preparation of the pure titanium dioxide. Through the aerosol-assisted technology and our self-made setup, a kind of titanium dioxide with higher activity than commercial product P25 was successfully fabricated, while this aerosol-assisted process takes only about 10 s. By adjusting the operation temperature, the obtained titanium dioxide nanoparticles have different crystalline sizes and phase compositions, which are two major factors determining the catalytic activity of the materials. The results show that the optimum temperature was 600 degrees C, and the AST-600 particle prepared under this condition has the rate constant at 1.49 in the removal of methyl orange, which is 2.36 times that of Degussa P25. Although the AST-600 particle could only be activated by UV light similar to P25, the efficiency of AST-600/g-C3N4 is higher than that of P25/g-C3N4 under the visible condition. Meanwhile, the as-prepared titanium dioxide particles have been thoroughly characterized by TEM, SEM, XRD, PL, XPS, DRS, Raman and nitrogen adsorption in the study. Hence, we prepared a pure titanium dioxide with higher catalytic activity than P25, but the process is still very convenient, low cost and easy to scale up, holding great potential as an alternative to commercial product P25.