Integrated gasification combined cycle (IGCC) is an efficient and environment-friendly power generation system which is capable of burning low-ranked coals and other renewable resources such as biofuels, petcokes and residues. In this study some process modeling on a conceptual entrained flow gasifier was conducted using the ASPEN Plus process simulator. The layout of the model includes a pressurized entrained flow gasify reactor, a series of purification gas unit, COS hydrolysis reactor, MDEA column. One of purposes of this simulation is an effective approach for simulation gasification system. The effects of change of heat duty and pressure in the gasify reactor on the gasification process are studied by sensitivity analysis using developed model.