Abstract: Jacketed heat pipe of a five-stage economizer bursted during the operation, leading to leakage. The burst cause of the jacketed heat pipe was analyzed from the aspects of chemical composition, microstructure, hardness, fractography, etc. The results show that at the first start of operation, the heat pipe worked at an overheating temperature about 400℃. The steam pressure exceeded the burst pressure, causing the cracking of the outer pipe. After the outer pipe cracked, the water in the pipe and the working medium between the inner and outer pipes flew out, reducing the cooling effect; the high temperature flue gas directly contacted the inner pipe, increasing the possibility of sulfuric acid dew point corrosion. Consequently, the burst of the inner pipe occurred after continuously running for three months. In actual operation, the operation process should be strictly controlled and the operation management should be strengthened to prevent the pipeline from overheating, thus preventing the similar failure from happening again.