Abstract: In coal gasfication,the molten coal slag corrodes the refractory lining of the entrained-flow gasifier severely,which is an important factor affecting the life of refractory lining.The simulation device to study deposit of slag in double-nozzle-opposed gasifier is built in laboratory and paraffin is used as the medium.The experiment runs on different reaction conditions and its results show that deposit of slag need some time to reach static state.It is also observed that the higher of air temperature and air flux and medium temperature are,the less slag deposit thickness is,while the medium flux affect the deposit of slag little.The slag deposit is obviously thicker on ammonia-cooling part than that on the water-cooling part.