Molten salt oxidation is one of the most promising alternatives to incineration that can be used to efficiently destroy the organic components of mixed wastes and hazardous wastes. In this study, the gas holdup and gas-liquid flow characteristics are investigated in the molten salt oxidation reactor (0.076 m D.×0.653 m H.). Effects of input air velocity (0.05-0.22 m/s) and molten salt temperature (870-970 ℃) on the gas holdup and flow characteristics have been studied. Molten carbonate as the liquid phase and air as the gas phase have been used in this study. The gas holdup increases with increasing molten salt temperature due to the decrease of viscosity and surface tension of molten carbonate. The experimentally obtained gas holdups in the molten salt reactor have been well described and characterized by means of drift-flux model. The gas holdups with variation of the flow regime have been well predicted.