Abstract: The part of elevated temperature tensile test of materials in ASME and RCC-M specifications were compared and summarized in the aspects of elevated temperature tensile test equipment, sample size, test process and test result treatment. The results show that the specifications of ASME and RCC-M were quite different. For ASME more consideration was given to the effect of sample size and test temperature on the tensile test results, and it required higher accuracy and longer holding time. The range of loading rate required by the two specifications was similar, and the emphasis of the revision of the test results was different.