Highly transparent MgAlON ceramic was prepared by hot isostatic pressing (HIP) of the presintered compact using the MgAlON powder synthesized by carbothermal reduction and nitridation (CRN) method. Fine and low agglomerated MgAlON powder was synthesized at a relatively low temperature (1600°C) for 2h under N2 atmosphere. The MgAlON powder showed high sinterability with a bimodal particle size distribution at 0.3µm and 0.7µm. MgAlON ceramics were fabricated by pressureless presintering at 1840°C for 10h in N2 atmosphere and HIP at 1880°C for 2h in 190MPa Ar gas. The HIPed ceramic was fully dense with average grain sizes ~ 50µm. The in-line transmittance of the HIPed sample reached ~ 81.2% at 400nm and ~ 84.1% at 2500nm, respectively. The Vickers hardness and flexural strength of highly transparent MgAlON ceramic were 13.74 ± 0.15GPa and 268 ± 7MPa, respectively. The results demonstrate that our method has a promising future in transparent MgAlON ceramic production.