Abstract: Volumetric gas-liquid mass transfer coefficients were investigated in slurry bubble columns under elevated pressure and elevated temperature using a dynamic absorption method. The effects of system temperature, pressure, superficial gas velocity, concentration of solid on the volumetric mass transfer coefficients were discussed. The experimental results show that the system pressure, superficial gas velocity and concentration of solid are major factors affecting the mass transfer. The mass transfer coefficient increases with the increase of system pressure, temperature and superficial gas velocity, and decreases with the increase of solid concentration. Based on the experimental data, a correlation for the volumetric gas-liquid mass transfer coefficient of H2, CO, CO2 is obtained.