SiC nanowires were prepared via low pressure chemical vapor infiltration (LPCVI) technique in the sintered porous SiC ceramics.The average diameter of SiC nanowires changed from 200 to 1000nm when varying α from 50 to 80 on the porous SiC ceramics surface.SEM results revealed the diameter and shape of SiC nanowires decreased from the surface to the interior with duration of LPCVl.Additionally, the mechanical properties of porous SiC ceramics increased after the deposition of SiC nanowires.At α of 50, the increased ratios of flexural strength and fracture strength were 90.4% and 32.9%.The pressure drop level increased obviously with the gas velocity.The results indicated that the presence of SiC nanowires led to the change of apparent porosity, pore size and the microstructure, which worked together to affect pressure drop and permeability.