Abstract: The steam gasification kinetics of four different metamorphosed coals at mid-temperature (700~850℃) using potassium carbonate as catalyst was investigated with the isothermal thermogravimetric analysis under ambient pressure. The results show that the catalysis is greater for the high metamorphosed coal gasification. The integrated model and modified random pore model are good to correlate the relationships between carbon conversion and time for the case with potassium carbonate catalyst. However, the volumetric reaction model is poor in the fitting of data. The activity energy and pre-exponential factor were predicted from the modified random pore model. The activity energy of coal char catalytic gasification ranges from 90.317~167.861 kJ/mol. And there are compensation effects between reaction activity energy and pre-exponential factor.