<p>This study investigated the structural and performance characteristics of cellulose nanofibers (CNFs) prepared through Fe²⁺ assisted cold plasma (CP) pretreatment of cellulose. The results indicated that the high-energy active particles generated by Fe²⁺ assisted CP played a crucial role in the deconstruction of cellulose, resulting in CNFs with a more uniformly dispersed network structure, increased carboxyl content, and enhanced intramolecular hydrogen bonding. This effect was particularly pronounced at a working voltage of 60 kV. In addition, the mechanical properties of CNF films exhibited significant improvements in tensile strength and elongation at break. At a working voltage of 60 kV, the tensile strength and elongation at break of the CNF film increased by 21.79% and 78.91%, respectively, compared to that obtained without pretreatment. Compared to enzymatic pretreatment methods, the Fe²⁺ assisted CP pretreatment offered distinct advantages in both time efficiency and mechanical performance enhancement of CNF film. Considering the overall structure and properties of the CNFs, a working voltage of 60 kV was determined to be optimal for Fe²⁺ assisted CP pretreatment, yielding superior CNF performance.</p>