Transparent (Ce,Gd)(3)Al3Ga2O12 (Ce:GAGG) ceramics are promising scintillators for use in high-energy particle detection application such as nuclear medical imaging. In this study, we report a novel method for the preparation of transparent Ce:GAGG ceramic in oxygen atmosphere without sintering aid. The highest transmittance of as prepared samples with thickness of 1mm around wavelength of 558nm reaches 62%, which is close to that value of its comparative single crystal. The average grain size of samples sintered at 1650 degrees C for 10h is about 11m. The spectroscopic properties have also been investigated. The emission peak around 558nm, which is consistent with that of Ce:GAGG single crystals, matches well with the detection wavelength of photomultiplier.