Pure yttrium aluminum garnet (YAG) powders and the porous YAG ceramics were prepared via co-precipitation method andusing vacuum sintering technology, respectively. Through an analysis and discussion, porous YAG ceramics, with ahomogeneous and regular pore microstructure, a pore size of about 5 μm, regular crystalline particles, showing intergranularfracture, were sintered at 1500 oC. Porous YAG ceramics, with a homogeneous and regular pore microstructure, a pore sizefor about 2-5 μm, crystals with a rod-shape or acicular structure, showing intergranular fracture and intracrystalline fracture,were sintered at 1550 oC. Porous YAG ceramics, with an extension pore microstructure, a crystalline laminate structure,showing intracrystalline fracture, were sintered at 1600 oC. With an increase in the sintering temperature, the porosity isdecreased gradually and the energy consumption is increased. The best sintering temperature for porous YAG ceramics wasdecided to be 1550 oC through considering the performance price ratio among the porosity, the mechanical properties and theenergy consumption.