Abstract: Corrosion perforation was found in the distribution pipe and overhead circulation pipeline of the overhead circulation system of the coal-to-hydrogen acid water stripper. In this paper, systematic research and mechanism analysis on the corrosion failure phenomenon were carried out by combining corrosion morphology observation, microstructure analysis, corrosion product detection and process medium anslysis. The results show that the perforation of the distribution pipe and overhead circulation pipeline was the result of the synergistic effect of acid water corrosion and scouring. The presence of media such as ammonium salt and ferrocyanide further promoted the occurrence and development of erosion corrosion, eventually leading to corrosion perforation. Based on the analysis results, targeted control measures such as controlling flow rate, optimizing process operation and upgrading materials are proposed to provide technical support for the stable operation of the device.