Abstract: According to the forming process and structural characteristics of foamed ceramics, the method of selecting voxels of X-ray computed tomography (X-CT) based on the structure details of scanning electron microscope (SEM) analysis and selecting gray threshold based on the formation and characteristics of pores was determined. Through tomographic images, X-CT three-dimensional reconstruction and visual analysis, the fact that the foamed ceramic consists of large pores and small pores on the pore wall was obtained. The foam ceramic pores are basically in a connected state, and the connection is caused by small holes in the cell wall. Furthermore, the maximum connected pore diameter is not more than 60 μm, and the minimum connected pore diameter is about 14 μm are demonstrated. It shows that the pore diameter of the foamed ceramic macropore is between 0.5 and 1.0 mm, the maximum pore diameter not more than 2 mm, and the porosity is 85.97%. The thickness of the wall is concentrated between 20 and 60 μm. The research shows that X-CT has obvious advantages in studying the spatial structure relationship (i.e. connectivity) of foam ceramic pores and the statistical information (pore size distribution, wall thickness distribution, etc.) of large-size structure of foam materials.