CeO2 was doped in Tb3Al5O12 (TAG) magneto-optical transparent ceramics which were synthesized by solid state reaction and vacuum sintering. All the samples were highly transparent, the XRD results showed no secondary phases, and the XANES manifested that almost all Tb ions in the samples are trivalent. The experiment results proved that CeO2 could be the sintering aid for the fabrication of TAG transparent ceramics. The Ce-doping has an obvious effect on controlling average grain size, homogenizing grain size, and eliminating pores. The optimized addition of CeO2 was about 0.1 at%, and the sample presented excellent properties that the optical transmittance was 78 % in the region of 550-1500 nm; the microstructure revealed the most uniform grain sizes and almost pore free.