The reaction chamber of SiC high-temperature activated annealing furnace has high temperature and complex structure,it is easy to cause uneven temperature in the reaction chamber with passing the process gas,which affects product quality.In order to obtain a highly uniform temperature field reaction chamber,a physical model of the reaction chamber was established based on the equipment data of the annealing furnace.Based on solid and fluid heat transfer,surface-to-surface radiation heat transfer models,etc,COMSOL Multiphysics 6.0 system was used to build a simulation model of annealing furnace reaction chamber.The temperature distribution of the annealing furnace reaction chamber was simulated by changing the structure of the process pipe and liner pipe,optimizing the heater distance,gas flow,heat insulation screen height and other parameters.The results show that when the process pipe and liner pipe are made into a nested structure,the heater distance is 9 mm,the flow is set to 25 L/min,and the height of the heat insulation screen is 178 mm,the maximum temperature difference is reduced from 340 ℃ to ±4 ℃,and the uniformity of the temperature field in the reaction chamber is optimized.