BaTiO3(BTO) and SrTiO3(STO) ultra thin films of 1-10 unit cell layers are successfully fabricated on STO(0 0 1) substrates by laser molecular beam epitaxy. Measurements of atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM) and X-ray small-angle reflectivity reveal that the surfaces and interfaces are atom-level-smooth. The unit cell layers and the lattice structure are perfect.