Aiming at the problem of the heat is transferred from the cartridge case to the chamber during firing, the heat was absorbed and taken away from the chamber by the cartridge case during ejection, coupled field simulation methods is complicated in calculation and low in efficience, a simulation method of the temperature field of the gun barrel based on the birth and death element method was proposed. Based on ANSYS-APDL software, a simulation scheme based on different extraction times of a certain machine gun with 60 rounds of air cooling for 3 minutes and then 60 rounds of air cooling for 3 minutes was designed, and the simulation scheme of barrel temperature field was carried out when the shell and barrel heat exchange were not considered and the shell was fired without shells. The results show that the simulation method of gun barrel temperature field based on the death and death element method can take into account the heat exchange between the cartridge case and the chamber of the gun in the shooting process, and the difference of the extraction time will have a certain effect on the temperature field of the gun barrel.