Abstract: The entrained-flow pulverized coal gasification process was thermodynamically analyzed by Gibbs free energy minimization method. For a given coal , the effects of oxygen-coal ratio and steam-coal ratio on the crude syngas composition, gasification temperature and the yield of CO+H2 were studied under the operating pressure of 3.0 MPa and gasification temperature ranging from 1 200 ℃ to 1 450 ℃. The thermodynamic analysis results of the reasonable operation ranges (545 m3/t to 605 m3/t coal for oxygen-coal ratio and 152.64 kg to 319.32 kg steam/t coal for steam-coal ratio) and the corresponding gasification performance (typically, CO+H2 91.5 v%(dry base), gasification temperature 1 358 ℃ and syngas yied of 2.123 CO+H2 m3/kg coal) are obtained. At the same time, the study of the effects of carbon conversion efficiency and heat lost on the gasification performance shows that the effects are remarkable.