The LaAlO 3 films were grown epitaxially on Si (100) substrates by inserting SrO or SrTiO 3 buffer layer using a computer-controlled laser molecular beam epitaxy system. Structural characterization indicated that the LaAlO 3 films were two-dimensional layer-by-layer growth. The atomic force microscopy observations showed that the surfaces of the epitaxial LaAlO 3 films were atomically smooth. The crystallinity of the LaAlO 3 films determined by X-ray diffraction and high-resolution transmission electron microscopy was a single-crystalline structure. After being annealed at 1050°C in N 2 for 5min, the crystallinity of the LaAlO 3 film improved obviously. The successful LaAlO 3 /SrO/Si and LaAlO 3 /SrTiO 3 /Si epitaxial growth predicted that the possibility of the development of 3D heterostructrues on Si in a new generation of microelectronics devices.