<p>Understanding the interactions between hydrogen and metals with different crystal structures is crucial for developing materials for hydrogen storage and transport. This study uses molecular dynamics simulations to investigate how crystal structures and defect types influence hydrogen diffusion in iron and the effect of applied electric fields. The results show that the interaction between hydrogen and defects exhibits pronounced crystallographic specificity. In body-centered cubic iron, defects act as hydrogen traps, hindering the diffusion behavior of hydrogen atoms. Conversely, in face-centered cubic iron, defects serve as fast diffusion channels for hydrogen atoms, accelerating their diffusion. Under the action of an external electric field, the diffusion rate of hydrogen atoms in iron is accelerated. Therefore, this study provides new insights and solutions for designing new materials for hydrogen energy storage and transportation from the perspectives of crystal structure, defects, and applied electric fields.</p>