Abstract: A physical thermal model of COREX melter gasifier was established. The data of the air temperatures in this model were measured with temperature sensors under different experimental conditions. The temperature gradient could be obtained by processing the data of the air temperatures in this model. The results showed that the packed bed, cohesive zone, drip zone and raceway in the melter gasifier could be roughly distinguished by analyzing temperature gradient along the vertical direction. The zones in the COREX melter gasifier could be described objectively by the method so as to analyze the impact of the operating conditions on the zones in the future studies.