Abstract: An apparatus was designed and constructed capable of measuring the permeability of unidirectional fiber bundles. In order to analyse the axial permeation，saturated and unsaturated permeabilities were compared，and the influences of pressure type，fiber volume fraction and types of liquid on the unsaturated permeability were investigated. It is found that the saturated permeability is bigger than unsaturated permeability under the same test condition，and the influence of capillary force on unsaturated permeability reduces with increasing the external pressure. Besides，as the fiber volume fraction increases，the permeability declines and the permeability from the vacuum drive test is larger than that from the air drive test under the same pressure.