Abstract: Long start-up period and more SO2 emission are the two problems existing in Claus tail gas hydrogenation process. To solve the problems, a sulfidation technology in advance of hydrogenation catalyst is applied for the first time in the No.2 100kt/a sulfur recovery plant of Zhenhai Refining & Chemical Company. The advantages and difficulties of the sulfidation technology in advance and the procedures were analyzed and introduced in detail. The application results show that the technology can satisfy the working need of the unit and cut the start-up time, save fuel and electricity consumption, and reduce the SO2 emissions.