Abstract: One of the most important deformation modes in resin transfer molding (RTM) of manufacturing processes is compression along thickness direction, which reduces the thickness of the textile preform and causes the change of the fabric structure, causing the nesting effect. Nesting reduces the laminate thickness, increases the fibre volume fraction, and changes the porosity pattern. The effect of adjacent fabric layer nesting has a certain spatial dispersion. This makes the fabric permeability variable. In this work, an experimental device was designed to measure the spatial dispersion of local permeability for low viscosity resins. Then, a random nested monocyte model was established, ANSYS/CFX finite element software was used to realize the numerical simulation of single cell, and the local permeability was obtained by flow analysis. The statistical distribution of permeability was then studied. The experimental results were compared with the numerical simulation results. The reliability of the numerical simulation results was verified. Finally, the random permeability field was established based on the statistical distribution of permeability, and the numerical simulation of resin filling was carried out. The results show that this method is more advanced than traditional method based on constant permeability. The results can provide a basis for the robustness optimization of RTM process in the future.