The phase change films were deposited on K 9 glass substrate by RF magnetron sputtering technique with an Ag In Sb Te alloy target. The as deposited films were annealed at 300 ℃. The influences of background pressure, sputtering pressure and sputtering power on the optical properties of the phase change films are studied. It was found that the optical properties of the phase change films were synthetically determined by sputtering parameters and lower background pressure, while the proper sputtering pressure and sputtering power were very important for the AgInSbTe phase change films.