The ablation properties and morphologies of carbon/carbon (C/C) composites with tungsten carbide (WC). laments were investigated by ablation test on an arc heater and scanning electron microscopy. And the results were compared with those without tungsten carbide (WC). laments tested under the same conditions. It shows that there is a big difference between C/C composites with and without WC. laments on both macroscopic and microscopic ablation morphologies and the ablation rates of the former are higher than the latter. It is found that the ablation process of C/C composites with WC. laments includes oxidation of carbon fibers, carbon matrices and WC, melting of WC and WO3, and denudation of WC, WO3 and C/C composites. Oxidation and melting of WC leads to the formation of holes in z directional carbon fiber bundles, which increases the coarseness of the ablation surfaces of the composites, speeds up ablation and leads to the higher ablation rate. Moreover, it is further found that the molten WC and WO3 cannot form a continuous film on the ablation surface to prevent further ablation of C/C composites. (c) 2009 Elsevier B.V. All rights reserved.