In order to simulate the cohesive zone of COREX melter gasifier, a physical thermal model was established, and the state inside the model was simulated with the particles of wax and maize. The influences of operating parameters, such as melting rate, ore / (lump coal + coke) volume ratio, raceway gas temperature and raceway gas volume on the cohesive zone were studied in the experiment. The change of the cohesive zone was also analyzed under different operating conditions.