<p>Materials with excellent soft magnetic properties are widely used in power electronics and high frequency sensor applications. The development of soft magnetic materials with excellent corrosion resistance has become crucial. Though FeCo alloys possess excellent magnetic properties, such as high saturation magnetization (<i>Ms</i>), their insufficient corrosion resistance severely limits practical applications. In this study, (Fe₇₀Co₃₀)_{100–<i>x</i>}Cr_<i>x</i> (<i>x</i> = 0, 5, 10, and 15) alloys were prepared using vacuum induction melting. The phase composition and microstructural morphology were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of Cr content on magnetic properties and corrosion resistance were systematically investigated. The study found that the addition of Cr induced changes in phase composition, and the magnetic dilution exhibited by Cr led to a decrease in the <i>Ms</i> of the (Fe₇₀Co₃₀)_{100–<i>x</i>}Cr_<i>x</i> alloy. Furthermore, the magnetic moment and density of states of the alloy were verified through first-principles calculations. Density functional theory (DFT) suggests that Cr atoms undergo a ferromagnetic transformation, attributed to strong hybridization of electronic states. This finding is corroborated by our experimental results. Notably, the addition of Cr significantly enhances the alloy’s corrosion resistance, as evidenced by electrochemical measurements showing a reduced corrosion current density and suppressed tendency for self-corrosion. These findings provide valuable insights for electronic material applications and the development of soft magnetic materials with both excellent corrosion resistance and magnetic properties.</p>