It is well recognized that PDS desulfurization and decyanation process is widely used in crude gas treatment for its high removal efficiency and stable operation in coking industry.In actual production,however,the desulfurization liquid may accumulate in the system and has to be partially disposed as waste liquid,which would not just increase the operating cost,but cause waste of the PDS catalyst.Based on water balance calculation,the operating regime has been optimized so that the water balance can be realized in the process of PDS desulfurization and decyanation.