Abstract: The reheat hot leg elbow of 15Cr1Mo1V steel with longitudinal weld, which has been in service for 1.4×10⁵h in a power plant, was taken as the research object. The geometric size, chemical composition, mechanical properties at room temperature and high temperature, and microstructure were studied, and its safe service state was analyzed. The results show that after 1.4×10⁵h high-temperature service, the base metal of 15Cr1Mo1V elbow with longitudinal weld and the two longitudinal welds are in good condition, and no obvious accelerated aging deterioration is found in the microstructure and properties. The creep life evaluation results based on the endurance test show that the elbow welded joint has a creep life of more than 10⁵h.