Epitaxial SrTiO3(STO) film on epitaxial (Ti,Al)N/Si(100) was successfully obtained using a Ti-buffer layer. The SrTiO3 film was (100) oriented and grew in parallel epitaxial relationship (cube-on-cube), i.e., (100)SrTiO3//(100)(Ti,Al)N//(100)Si, <110> SrTiO3//<110> (Ti,Al)N//<110> Si. The Ti-buffer layer was grown on (Ti,Al)N by magnetron sputtering, and the thickness of the buffer layer was 2-10 nm. After the STO film was sputtered, the Ti-buffer layer was changed to polycrystalline anatase-TiO2.