Abstract: In a composite system, the adhesion at the interface between fiber and matrix plays an important role in improving the resulting mechanical behavior. However, interfacial adhesion cannot be achieved without intimate contact. Impregnation flows in T300 and T700 carbon fiber beds were tested when penetrated by a 618 epoxy resin and a AG80 epoxy resin, in both longitudinal and transverse directions. The effects of temperature and fiber volume fraction on the impregnation performance were investigated. Results show that capillary impregnation in the transverse direction is much lower than impregnation in the longitudinal direction. Different trends were found in the analysis of the effect of fiber volume fraction on capillary impregnation in these two directions. With increasing fiber volume fraction, the wicking height increases in the longitudinal impregnation, however, it decreases in the transverse impregnation.