This standard specifies the test principles, conditions, equipment, samples, steps, data processing and quality control of radioactive materials transport containers in heat resistance test. It is applicable to the heat resistance evaluation of radioactive materials transport containers. Miscellaneous equipment heat resistance test can also be carried out with reference to this standard. This standard refers to the relevant standards such as the regulations for the safe transportation of radioactive materials and the test methods for the safety of radioactive materials transport containers to ensure the scientific and Reliability of the test process. The implementation of GB/T 43257.6-2023 helps to evaluate the Stability and safety of radioactive materials transport containers in high temperature environment, and provides technical support and guarantee for the transportation of radioactive materials.