Abstract: Ultra-high performance concrete (UHPC) is widely used in the field of construction engineering due to its excellent mechanical properties and durability. Fiber implantation technology can significantly enhance the light transmittance and functional integration of UHPC, but the mechanism by which its porosity affects comprehensive performance remains unclear. Existing research has primarily focused on the iMPact of fiber quantity on light transmittance and the strength of materials or reinforced fiber composites. However, there is limited research on the bending capacity of special panels, especially the bending performance under different porosity rates. Therefore, this paper aims to systematically investigate the influence of hole distribution patterns and fiber porosity (0.1% to 1.0%) on the bending strength, toughness, and durability of UHPC panels. This paper employs numerical simulation methods to systematically study the effects of different hole distribution patterns and fiber porosity on the bending strength, toughness, and durability of UHPC panels. By simulating the mechanical properties under different porosity rates and distribution patterns, the bending capacity under uniformly distributed load is analyzed. The results indicate that among different distribution patterns, panels with dense fiber holes exhibit poorer bending capacity. Among various fiber hole distribution patterns, those with a higher degree of density show slightly weaker bending capacity, but the difference is minimal and almost negligible. When the porosity rate is ≤1.0%, the mechanical properties tend to stabilize at a porosity rate of approximately 0.4%. It is recommended that the design of transparent UHPC use a porosity rate of 0.4% as a critical value, combined with randomly graded hole distribution, to balance light transmittance and mechanical properties. The research results provide a theoretical basis for the engineering application of transparent UHPC.