Abstract: The hydrogen sulfide stripper C-202 was added and put into use after the upgrading and revamp of certain diesel continuous liquid phase hydro-treating unit in October 2016. After being used, the stability of diesel quality was improved greatly. But in June 8, 2017, wall leakage was found at the seventeenth layer intake port of C-202 tower. This paper analyzes the causes for the wall leakage of C-202 tower in detail from such aspects as tower material, design operating conditions, actual operating conditions and corrosion. The causes for the wall leakage of C-202 tower are found out and the corresponding countermeasures are put forward