FeNiN-system materials have a very large magnetic moment that is attractive to be used for high frequencies devices. This investigation focused on magnetic properties of the FeNiN thin films deposited on a substrate at 200^oC by magnetron sputtering followed by annealing for 60 min. The energy of exchange coupling for the Fe₃NiN thin film deposited at N₂ flow ratio F_N2 10 % measured was about 1.5 eV from XPS spectrum. The magnetic moment of the Fe₃NiN thin film (F_N2 = 10 %) was estimated as 7.13 μ_B based on energy-distribution spectrum shown by XPS measurement. On the other hand, the magnetic moment of the film was evaluated as 7.13 μ_B based on the lattice constant; a = 0.377 nm that was calculated with a XRD profile, and its magnetization was calculated as I_S = 15.5 kG.