Based on the investigation on the strategy, effect and experience in the purging of super high pressure steam pipelines, this paper takes According to the characteristics of C₅ diolefins，which are prone to self-polymerization and copolymerization, and combined with the actual production of C₅ separation unit，this paper analyzes the influence of factors such as unit consumption of polymerization inhibitor，hydrolysate of DMF，free oxygen content in system，temperature in tower and diolefin concentration on the polymerization inhibition effect of polymerization inhibitor, and reasonably optimizes these factors. After optimization，the production stability of the extraction and separation system is improved obviously, the cleaning frequency of pump inlet filter decreases, and the operation cycle of reboiler is extended. The results show that the polymerization coking rate of diolefin remarkably decreases, the yields of the target products of C₅ separation unit are improved，the operating cost is reduced，and the operation cycle of the extraction and separation system is extended.