The syngas composition characteristic was investigated in the real slurry-feed gasifier using a detailed gas phase reaction mechanism. The results show that the time for syngas to reach equilibrium is much shorter than the residence time for slurry feed entrained-flow gasifiers, indicating a gas phase species partial equilibrium state. Further calculation shows that the four major species, CO, CO2, H2, and H2O, are in equilibrium via the reaction . Suggestions are provided for future modeling and model validation.