Based on chromatographic theory, the moment method and the time-domain fitting analysis wereapplied to measure and evaluate the adsorption equilibrium constant and mass transfer properties (axial dispersioncoefficient and effective intra- particle diffusivity) for toluene and p-dichlorobenzene on silica gel adsorbent in thesubcritical and supercritical CO2. An apparatus based on supercritical fluid chromatography was established and theexperiments were performed at temperatures of 298.15-318.15 K and pressures of 7.5-17.8 MPa. The two methodshave been compared. The results show that for the systems studied here the moment method can give reasonablevalues for both adsorption equilibrium constant and mass transfer properties, but the time-domain analysis only canobtain the adsorption equilibrium constant. The dependence of adsorption equilibrium constant and mass transferproperties on temperature and pressure was investigated.