Abstract: Well-cubic perovskite lanthanum aluminate (LaAlO₃) film on (110) silicon substrate was fabricated by sol-gel method with corresponding inorganic salts. Lanthanum acetate and aluminum acetate glacial acetic acid solutions were prepared via ligand exchange starting from lanthanum nitrate hexahydrate and aluminum nitrate hexahydrate after being refluxed. (CH₃CO)₂O removed nitrates and the crystallized H₂O completely, acetylacetone (AcAc) was partially bidentated with metallic ion of the metallic acetates and formed La(OAc)₃-x(AcAc)x, which were hydrolyzed into La(AcAc)_3-x(OH)_x by adding 10 ml 0.4% methyl cellulose (MCL) solution. The La(AcAc)_3-x(OH)_x, polymerizing and combining with MCL, formed the LaAlO₃ sol precursor with heteropolymeric structure and formed film easily. The epitaxial laAlO₃ film on Si(110) substrate was crystallized after being annealed in thermal annealing furnace for 650-750 °C/30 min. The morphologies and microstructures were characterized. The refractive index of the LAO film was 1.942 to 2.007; the dielectric constant and the dissipation factors were estimated to be 23-26 and 2.1×10^-4-2.4×10^-4respectively.