Porous ceramics incorporate pores to improve several properties including thermal insulation, maintaining inherent ceramic properties such as corrosion resistance and large mechanical strength. Conventional porous ceramics are usually fabricated through an insufficient sintering, leading to degraded strength and durability. Contrary to this, we have innovated superplastically foaming method to make ceramic foam only in the solid state. In this method, the previously inserted foam agent evaporates after the full densification of matrix at around the sintering temperature. Closed pores expand utilizing the superplastic deformation driven by the evolved gas pressure. Based on this concept we fabricated 8mol% yttria stabilized zirconia based porous ceramics and examined the properties concerning the high temperature structural material with thermal insulation.