The microstructure of domestic automated placement dry fibers was characterized and analyzed, with a comparative analysis against imported materials. Using a self-made glass mold and adopting the central injection method, the number of layers of domestic automated placement dry fibers was varied. Based on Darcy’s law, the permeability of domestic dry fibers was calculated, and the factors influencing their permeability were explored. The results indicate that domestic dry fibers share the same three-layer structure in microstructure as the imported dry fiber TX1100. The average diameter of fibers in the mesh layer of domestic dry fibers is 20 μm, three times that of TX1100. At the same layer count, the permeability in the X-direction is approximately twice that in the Y-direction. As the number of layers increases, the permeability in both X and Y directions rises, while penetration in the Z-direction is relatively difficult. Additionally, the permeability of dry fiber brand 231016FH is higher than that of 231227FH, and the fibers in the composite formed by 231016FH are arranged more tightly.