Abstract: When tunnel type food fryer is running, deformation of tank body when it is heated will affect operation stability of fryer．The maximum deformation of traditional "U" shaped tank has reached 20 mm, resulting in frequent failures of transportation, slag removal and other mechanisms, which has been plaguing equipment manufacturers．Thermal deformation of tank body of buffer tank structure fryer is small．Due to defects such as incomplete slag removal and inconvenient cleaning, it is not conducive to widespread promotion．The minimum thermal deformation of tank body of the "H" shaped tank structure frying machine could be controlled below 6 mm．Under this deformation, operation stability of whole machine can be improved, and it is not difficult to process．This technology can be promoted and applied in tunnel type food fryer．