A unique process, which consists of camphene-based freeze-casting and reactive sintering, has been developed to fabricate highly porous Cr3C2 ceramics, which were featured with a well-defined multisize porous structure, consisting of large pore channels throughout the sample and small pores on the porous struts. The porous structure was found to be affected by the solid loading content and the casting temperature. Decreasing the solid loading content or increasing the freezing temperature increased the size of large pore channels. However, the size of small pore was not significantly influenced by the variation in the freeze-casting parameters. Compared with other techniques reported for the fabrication of porous ceramics, high porosity can easily be achieved by this method. The sintering mechanism of the formation of the porous structure was also discussed in this study.