A perovskite type of (La, Sr)MnO₃ films were deposited on SiO₂/Si substrates with amorphous surface by using the facing targets sputtering system. La_1-xSr_xMn_yO₃ targets were prepared by the conventional sintering method from starting powders of La₂O₃, SrCO₃, and Mn₃O₄. The Sr and Mn content were strongly affected whether the sputtering gas has included oxygen or not. The film as-deposited at partial O₂ pressure Po₂ of 0.04m Torr was composed of crystallites with excellent (100) orientation at relatively low substrate temperature T_s. Whether the sputtering gas has included oxygen or not also affected the crystallinity of the films. The 4πM_s of as-deposited films increased after post-annealing process, and has reached near that of bulk La_1-xSr_xMn_yO₃. The increase of 4πMs seems to be caused by the compensation of the lack of oxygen ions in the perovskite crystal structure. Since the MR response of the films exhibits excellent linearity, these LSMO films seem to be applied for magnetic sensor devices. The linear MR response has remained after post-annealing process.