The invention discloses a porous oxide ceramic (aluminum silicate, mullite, alumina ceramics) prepared according to a foam in-situ consolidation method. Porous aluminum silicate, mullite, alumina ceramics each are made from the following raw materials: kaolin, bauxite, silicon micropowder, aluminum oxide and quartz, as well as a gas-generating agent (metal aluminum powder, rosin soap or sodium lauryl sulfate, polyvinyl alcohol or sodium carboxymethyl cellulose, agar), a foaming agent, a foam stabilizer and a forming agent. The porous oxide ceramic is prepared by the following steps: (1) preparation of ceramic slurry; (2) foaming of the slurry; (3) in-situ injection-consolidation forming of the slurry; and (4) drying and burning of formed blanks. The porous oxide ceramic heat insulating material has a uniform distribution of porosity and is good in heat-insulating effect and thermal shock resistance. According to the method, the process is simple, the cost is low, heat insulating materials for high-temperature kilns working in different temperatures (1200-1600 DEG C) can be produced, the heat insulating material product is not liable to chalking or cracking during long-term use, and the service life of the porous oxide ceramic heat insulating material is prolonged when compared with that of the existing kiln heat insulating material.