In this paper, TiO2 nanopowders are produced by gas-phase detonation method. The powders are analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and specific surface area determination. The results indicate that the powders are mixed crystal of rutile and anatase, and have good dispersibility and high specific surface area. Also, the particle sizes of powders are between 40 to 200 nm which are spheroid and cube. The measurement data of detonation pressures shows that the reaction took place under a deflagration to detonation transition (DDT).