Transition metal carbide, especially one-dimensional (1D) hafnium carbide (HfC), have attracted increasing attention from researchers of ultra-high temperature field. Herein, we used chemical vapor deposition method to fabricate 1D HfC including HfC nanowries (HfCNWs) and whiskers (HfCWs) in carbon/carbon (C/C) composites to construct three dimensional HfCNWs-C/C and HfCWs-C/C networks composites. Results showed that the HfCNWs and HfCWs were radially and evenly distributed on the surface of carbon fibers. The in situ grown HfCNWs and HfCWs decreased cracks in pyrocarbon matrix. Benefiting from the unique chemical and physical properties of 1D HfC, the HfCNWs-C/C composites exhibit improved thermal conductivity and ablation-resistance.