Abstract: The post weld heat treatment of T91 pipe seat weld was carried out by using veneer induction heating and winding induction heating, respectively. The temperature curves of post weld heat treatment using different induction heating methods were measured and the temperature distribution characteristics were analyzed. The results show that due to serious electromagnetic offset with veneer induction heating, the current required to heat to the set temperature increases sharply,exceeding the rated current of the equipment, and it is not suitable for pipe seat weld heat treatment. When winding induction heating is used, the smaller the number of winding coils on the small tube, the smaller the temperature difference between upper and lower tubes. When the number of winding coils on the small tube is 0, after insulation at 760 ℃ for 20 min, the temperature is 750-760 ℃, and good annealing effect can be obtained. Different heating speeds have little effect on the temperature distribution. Therefore, on the premise of meeting the use of the equipment, the heating speed can be accelerated and the heating time can be shortened. In order to deal with the sudden change of the current, when the heating temperature reaches 700 ℃, set the heating speed of 200 ℃/h during heating to 760 ℃, the temperature difference of each point is within10 ℃, and the heating effect is good.