Abstract: A mesostructures model of the plain weave fabric was set up. The homogenization method was introduced to predict the permeability of the plain fabric preform. The results of the permeability obtained by the approach were compared with the experimental results in the literature，and it shows good agreement. The influence of the mesostructures parameters on the permeability was discussed. The permeabilities of three kinds of plain glass fabrics were measured and the results were compared with the predicttion. It shows that the permeability obtained by the present method is at the same order of magnitude as the experimental results.