(Fe83Co17)xAg100-x granular films (x=40, 45, 50, 55, 60) were grown on the substrates of glass using the magnetron sputtering system. The structure, GMR and magnetic property of (Fe83Co17)55Ag45 granular film, which were as-deposited and vacuum annealed, were studied by X-ray diffraction (XRD), a four-point probe method and a vibrating sample magnetometer (VSM). The results of magnetic resistance measurement show that GMR of the sample (Fe83Co17)55Ag45 granular film with 400 nm thickness gets the maximum, –8.1%. XRD results show that microstructure of (Fe83Co17)55Ag45 granular film has changed, which leads GMR to firstly increase and then decrease, and the maximum is –8.3% at 150 °C. Meanwhile, the magnetic hysteresis loop illustrates that the coercive force of (Fe83Co17)55Ag45 granular film increases with the annealing temperature increasing