LSMO films with various thicknesses were prepared on single crystal Si (111) substrates by sol-gel process. The films were dense and had a uniform microstructure. The films showed metallic conduction characteristics at low temperature and insulator characteristics at high temperature. The metal-insulator transition temperatures (Tmi) of the films were remarkably lower than that of the bulk ceramics. The effect is related to the distortion of crystal lattice resulted from the residual stress in the films.