To meet the demand for structural–functional integrated materials in extreme service environments, this paper focuses on Fe-Si porous materials. This system, based on mixed metallic–covalent bonding, bridges the gap between the insufficient creep resistance of porous metals and the brittleness of porous ceramics, while offering designable porosity and high-temperature oxidation and corrosion resistance, and is penetrating engineering applications. The pore-formation mechanisms of powder reactive sintering, dealloying, sacrificial templating, and additive manufacturing are systematically reviewed, and their configurational complexity, preparation efficiency, and feasibility for continuous production are compared. Emphasizing pore-structure control, the governing roles of composition, sintering parameters, and phase-transformation kinetics on microstructural reconstruction are revealed, and the structure–property relationships among cross-scale pore characteristics (porosity, pore-size distribution, connectivity) and mechanical integrity, thermal stability, and permeation flux are clarified. Facing multi-field coupling conditions, the service characteristics and performance boundaries in high-temperature particle interception, damping dissipation, thermal management, and surface protection are summarized. Aiming at bottlenecks such as the strength–porosity inversion, limited pore customizability, and high batch-to-batch property dispersion, performance-optimization pathways are proposed from the perspectives of multi-dimensional composite strengthening, multi-level topology design, and intelligent additive manufacturing, providing theoretical and technical guidance for fundamental breakthroughs and full-chain engineering of Fe-Si porous materials.