Abstract: A differential thermal analyzer system able to work at 1500K(maximum) under 3.0 MPa in different gas atmosphere was built up and used to investigate the reaction kinetics of pressurized gasification of four typical coal or coal samples of different ranks by CO2 or steam. The results show that: 1 ) gasification of coal/char increases with the decrease of coal rank; 2 ) the influence of gasification pressure on reactivity can be expressed by for CO2 and for steam. A general model describing the reaction kinetics of pressurized gasification of coal/char by CO2 or steam was obtained as follows Compared with thermogravimetric analysis, this technique yields more accurate results.