Abstract: The structural and magnetic properties of the antiperovskite (Fe1-x Nx)4N compounds were investigated by employing a full potential linearized augmented plane wave method (FPLAPW)．The dependence of lattice constants on the content of Ni was calculated．The calculated results of total energy imply that Ni prefers to occupy the corner sites rather than the facecenter sites．The investigation of the dependence of the binding energy of (Fe1-x Nx)4N on the Ni content indicates that the stabilization of ( (Fe1-x Nx)4N increases firstly and then decreases. The compound reaches the most stabilization at x=0.25．After x0.75, it becomes unstable, which is agreed with the result of experiment very well．The effects of different exchange correlation potentials on the magnetic moment were discussed.