Abstract: To balance the contradiction of mechanical strength and air permeability of porous corundum materials, the calcium hexaluminate was in-situ synthesized in the porous materials by using pure calcium aluminate cement as the calcium source. The effects of in-situ synthesized calcium hexaluminate on the microstructure, phase composition, and mechanical properties of the porous corundum materials were investigated. The results show that, the plate-like calcium hexaluminate particles can be in-situ synthesized in the specimens added with pure calcium aluminate cement after treated at 1700 for 3 h. When the mass fraction of pure calcium℃aluminate cement is no more than 3%, the in-situ synthesized calcium hexaluminate not only improves the cold compressive strength and the high-temperature bending strength (1400℃×0.5 h) of the porous material, but also improves the air permeability of specimens. With further increase of pure calcium aluminate cement additions, the above properties of the specimens turn to a reversed trend. The cold compressive strength of specimen added with 3% pure calcium aluminate cement by mass is 33.6 MPa, the highest high-temperature bending strength is 6.2 MPa, and the Darcian permeability and non-Darcian permeability constant are 2.54×10^-10 m²and 1.46×10^-6 m, respectively.