SrTiO₃ nanocubes and their hyperstable nanocrystalline sols were synthesized by a rapid sol-precipitation method under atmospheric pressure. Using triethylene glycol (TEG) to control the hydrolysis rate of tetrabutyl titanate, the SrTiO₃ nanocrystalline sol was obtained in as little time as 2 h. The formation kinetics of the SrTiO₃ nanocubes indicated that controlled hydrolysis is critical to the generation of a well defined cubic shape. The Fourier transform infrared (FT-IR) spectrum confirms the existence of TEG molecules on the surface of the particles and explains the high dispersion of the nanocubes in polar solvents. Owing to the large specific surface area (99.065 m(2) g(-1)), cubic SrTiO₃ nanocrystals showed enhanced photocatalytic activity. A high-quality SrTiO₃ nanocrystal film was prepared by spin-coating of the hyperstable sol at 100-160 °C, providing a new low-temperature route for the fabrication of perovskite thin films.