Abstract: The chemical composition, mechanical properties, metallographic examination and energy spectrum analysis of the drum burst accident of the water wall of a circulating fluidized bed boiler in a power plant were carried out, and the numerical simulation of the failure pipeline was carried out combined with the pipeline and the joint inspection. The results show that the chemical composition and mechanical properties of the failed pipeline met the standard requirements, and there was no obvious abnormality in the metallographic test results. Foreign matter blockage and multiple bulges were found in the inspection of pipeline and joint box. Numerical simulation and strength check were used to confirm that foreign matter blockage was the direct cause of pipe explosion. At the same time, it was found that the local temperature to the fire surface was 550-730 ℃ when the failure pipeline was blocked.