Objective To analyze the influence of different materials on the thermal stress field of bipolar high-frequency electric knife. Methods Based on the ANSYS software, the electric-thermal coupling simulation analysis was performed for the thermal stress field of the bipolar high-frequency electric knife. The influence of 4 different insulating layer materials and 4 different electrode materials on the thermal stress field and thermal deformation field of insulating layer, electrode and coating of bipolar high-frequency electric knife and myocardial tissue were researched. Results For the 304 stainless steel, 316 stainless steel, 317 stainless steel and Ti6Al4V, the thermal deformation of myocardial tissue is much higher than that of the components of high-frequency electric knife in 2s for continuous power. From the point of view of protection myocardial tissue, 304 stainless steel is the best electrode material for high-frequency electric knife. For the four kinds of insulating materials of PP, PA6, PC and ABS, the thermal deformation of myocardial tissue caused by thermal stress is the smallest for PP, which can better maintain the integrity of tissue. Conclusions The manufacturing materials of high-frequency electric knife have an important influence on the thermal stress field in the working process. The regular analysis results can provide guidance for the development of high-frequency electric knife.