A series of (Fe40Co40B20)1-xNix magnetic thin films (x is atomic fraction) were synthesized by magnetron sputtering (RF), and the electromagnetic and microwave properties were investigated. The results show that the microstructure and electromagnetic properties of the films can be altered by varying the content of Ni addition and suitable process parameters. Excellent microwave properties and high resistivity are achieved in the (Fe40Co40B20)0.91Ni9 thin film. The film has the saturation magnetization 4πMs of 2.21 T, the real part of complex permeability μ' is larger than 195 at 0.5-3.0 GHz fFMR reaches to 3.16 GHz, and the resistivity is 276 μΩ·cm. Therefore, the presented films have the potential for the electromagnetic device design in the GHz frequency range.