SmFeN has received a lot of attention in recent years because of its exceptional wave-absorbing characteristics. Herein, nitro-SmFeN alloy powders were prepared by gas nitriding at 550^oC for 2 h and 3 h. Then the effect of nitriding treatment on their microstructure and electromagnetic parameters (including the dielectric real part ε′, the dielectric imaginary part ε″, the permeability real part μ′ and the permeability imaginary part μ″), attenuation constants, and impedance matching, as well as the influence on wave-absorbing properties were studied in detail. The findings indicate that the N content of SmFeN alloy powders can be increased due to the nitriding treatment, as a subsequence the the nitride structure of SmFeN is changed to Fe₃N and Fe₂N, therewith its wave absorbing performance is enhanced. Following nitriding, SmFeN's reflectivity value is significantly increased (with a minimum reflection loss value of -52.49 dB). Additionally, the effective absorption bandwidth is widened and moved to a lower frequency, with a maximum value of 4.3 GHz in the 10.4~14.7 GHz frequency range. The study's findings offer a useful concept for the ensuing relevant applications.