The work reports the direct epitaxial growth of SrTiO3 on Si (001) substrate by molecular beam epitaxy. The impact of the growth temperature and the initial oxygen partial pressure on the heteroepitaxy is studied in detail using different in-situ and ex-situ characterization methods. The optimal growth condition has been identified as 360 degrees C with the initial oxygen partial pressure of 5 x 10(-8) Torr to achieve a high-quality single crystalline SrTiO3 film and a coherent interface between SrTiO3 and Si. The THz Infrared (IR) measurements show that the biaxial strained SrTiO3 commensurately grown on silicon undergoes a cubic-tetragonal phase transition. (C) 2010 Published by Elsevier B.V.