This method mainly includes direct sintering method and pore-forming method. The powder direct sintering method is to use the sintering property of solid particles to mix the particles evenly and sinter at high temperature under a certain temperature system to obtain porous materials. The porous materials with uniform distribution of small pores can be economically prepared by this method. J.H.She et al. obtained high strength porous ceramics with porosity of 32.4% by sintering under a certain temperature system with alumina and silicon carbide as main raw materials and graphite as pore-forming agent. Xu Guogang and others used boehmite as the main raw material and yeast as pore-forming agent to prepare foam ceramic materials with certain pore size and uniform distribution.