The porous SiC ceramics were prepared by two methods of pore-forming. The gas permeability and flexural strength of the porous SiC ceramics prepared by different ways were investigated. The porous SiC ceramics prepared by particle stacking have evenly pore distrubution; the gas permeability was greatly increased with the particle size increasing while the porous SiC ceramics were kept a higher flexural strength. The pore-former also can be used to form large pores to increase the gas permieability. However, these unevenly distribution large pores lead to a deterioration in flexural strength.