Magnetic anisotropy and spin polarizability are recognized as the critical parameters determining the performance of ferromagnetic electrodes in spintronic devices. Fe₄N exhibits a high Curie temperature, high saturation magnetization, and good stability; however, the application in spintronic devices is limited by the low spin polarizability and in-plane magnetic anisotropy (IMA). Atomic doping is an effective method to modulate the magnetic properties of Fe₄N. As a heavy metal element, Pt exhibits a strong spin-orbit coupling (SOC) effect. Doping Pt into Fe₄N effectively enhances the overall SOC strength of the system, thereby realizing the regulation of the electronic structure and magnetic properties of the material. In this work, the electronic structure and magnetic properties of Pt^cFe₃N were investigated based on the first - principles calculations. The calculated results show that Pt^cFe₃N maintains a cubic anti-perovskite structure with a lattice constant of 3.856 Å. Phonon spectrum and ab initio molecular dynamics simulations confirm that Pt^cFe₃N possesses excellent dynamic and thermodynamic stability. The band structure calculations reveal that Pt^cFe₃N exhibits metallic properties. The band structure of Pt^cFe₃N shows no significant change upon the inclusion of SOC. The band distribution trends along all high-symmetry paths in the Brillouin zone are nearly identical whether SOC is considered or not. The total magnetic moment of Pt^cFe₃N is 8.18 μB without considering SOC. The atomic magnetic moments of FeII and Pt are 2.58 μB and 0.42 μB, respectively. The total magnetic moment of Pt^cFe₃N increases from 8.18 to 8.47 μB when SOC is considered, which is primarily due to the SOC-induced orbital contributions of 0.06 μB and 0.14 μB from the FeII and Pt atoms, respectively. The strong SOC associated with Pt atoms effectively lifts the d-orbital degeneracy and induces an orbital magnetic moment, which in turn enhances the total magnetic moment of the system. The spin polarizability of Pt^cFe₃N is -70.4%, which is 1.47 times larger than that of Fe₄N (- 47.9%). In addition, the incorporation of Pt atoms induces the transformation of Fe₄N from a weak IMA of 0.029 J/cm³ to a weak perpendicular magnetic anisotropy (PMA) of -0.003 J/cm³. The contributions of FeIIAa (5.104 J/cm³) and FeIIB (- 5.104 J/cm³) atoms to the MCA cancel each other in the system, and the Pt atom contributes an MCA of - 0.003 J/cm³, leading to a weak PMA in Pt^cFe₃N. In summary, Pt^cFe₃N exhibits a large magnetic moment, high spin polarizability, and weak PMA, demonstrating significant application potential in the field of next-generation spintronic devices.