<p>In a fusion reactor, tungsten materials are inevitably exposed to hydrogen, helium, and other particles, inducing irradiation damage that compromises the safety and reliability of the reactor. Surface quality directly governs the hydrogen and helium retention behavior of the material. To address the issues of poor material removal uniformity and processing-induced defects associated with conventional polishing, this study introduces a novel liquid film shearing polishing (LFSP) method. This method capitalizes on the shear rheological characteristics of non-Newtonian fluids in combination with the enhancement effect of a structured polishing plate, and is innovatively applied to the surface modification of tungsten to enhance its irradiation resistance. The surface quality of tungsten under different polishing conditions was systematically evaluated using white light interferometry and scanning electron microscopy, while hydrogen retention experiments were conducted to assess irradiation resistance. Furthermore, positron annihilation spectroscopy (PAS) and spherical&#xa0;aberration-corrected transmission electron microscopy (AC-TEM) were employed to reveal the relationship between processing-induced defects and irradiation performance. The results demonstrate that LFSP achieves almost defect-free surface planarization of tungsten, producing a smooth surface with a flatness of 0.05&#xa0;μm. Under comparable surface roughness levels, LFSP samples exhibited the lowest subsurface defect concentration and showed approximately 30% lower hydrogen retention than samples after mechanical polishing, indicating superior irradiation resistance. Moreover, PAS and AC-TEM results confirm that reducing subsurface processing defects is critical to enhancing tungsten’s resistance to irradiation damage. This study provides theoretical guidance for the mechanical processing of tungsten in future fusion reactors and provides valuable insights for the engineering application of tungsten materials.</p> Graphical abstract <p></p>