When the rectangular narrow channel is deformed due to radiation blistering,the flow heat transfer characteristics in the channel will be changed.In this study,the fluid pressure field and temperature field in the rectangular narrow channel under blistering condition is analyzed by numerical calculation method.The results show that the blocking effect of blistering on the fluid leads to a high pressure point before the first blistering.After each blistering,the local pressure drop suddenly rises first and then suddenly drops,causing the fluid temperature at the blistering to rise and the wall temperature to decrease.The influence of blistering conditions on the pressure and temperature fields is obtained through model calculation and analysis.