The invention relates to a method for preparing Re:YAG polycrystalline transparent 
ceramic by using different molding 
modes, which adopts commercial high-purity Y2O3, Al2O3 and Re2O3 as raw materials, adopts MgO, CaO or TEOS (
tetraethyl orthosilicate) as 
sintering additive, and prepares a raw blank by a cold isostatic pressing, slip 
casting or 
tape casting process to react and sinter the transparent polycrystalline Re:YAG 
ceramic. The method comprises the following steps: mixing and adding the oxides into a 
liquid medium; adding a certain amount of dispersant, 
adhesive, 
plasticizer, pressing agent and defoaming agent, carrying out ball milling, and mixing; treating the 
slurry under different conditions in different molding 
modes to obtain the raw blank; and 
sintering the degreased raw blank in a 
vacuum furnace. For the Re:YAG 
ceramic sintering body with thickness of 1.5mm, the 
transmission rate of straight light in the 
wavelength of 1064nm is not lower than 80% after the Re:YAG 
ceramic sintering body is subjected to double-sided 
polishing. For the raw blank which is prepared by different molding 
modes and is sintered for 10 hours at 1750 DEG C, sizes of ceramic grains are different, wherein regarding the raw blank prepared by cold isostatic pressing, the average grain of the ceramic is 13.5mu m; regarding the raw blank prepared by slip 
casting, the average grain of the ceramic is 3.5mu m; and regarding the raw blank prepared by 
tape casting, the average grain of the ceramic is 1.5mu m.