Abstract: Porous alumina ceramics were prepared by gel-casting method using alumina powder and hollow resin microspheres as the raw materials and isobutylene and maleic anhydride copolymer (PIBM) as dispersant and gelling agent. The microstructure and typical properties were characterized by X-ray diffractometer, scanning electron microscopy, universal testing machine, etc. The results showed that the addition of hollow resin microspheres could significantly improve the porosity of porous ceramics and also modify the pore structures. When the solid content of alumina reached 40%, the porosity could increase by 267% with the addition of 1% resin microspheres. Besides, the microstructure showed that the pores mostly distributed closed pores. The compressive strength and thermal conductivity of as-prepared porous alumina ceramic was about 50 MPa and 3.5 W/(m·K) at room temperature, respectively.