Porous silicon nitride ceramics have the properties of both silicon nitride ceramics and porous materials. They not only have the advantages of high strength, good toughness, creep resistance, structural stability, rain corrosion resistance and thermal shock resistance of silicon nitride ceramics, but also have the characteristics of low density, low dielectric constant and dielectric loss of porous materials. The excellent performance of porous silicon nitride ceramics determines that it has broad application prospects. Due to its high temperature resistance, corrosion resistance, thermal shock resistance, high opening, internal pores and other characteristics, porous silicon nitride ceramics are widely used in the fields of smoke and gas filtration, catalyst carrier and so on. They can also be used in the field of aerospace and aviation as radome materials used in harsh environments.