With the implementation of new environmental protection requirements, element chlorine is gradually enriched in iron and steel sintering system. In order to clarify the harm of element chlorine to sintering system, the effects of re-sintering of high-chlorine solid waste (mainly the dust removal ash in sintering electric field) on sintering pollutants, sintering system and flue gas purification system are studied and analyzed by sintering cup experimental simulation combined with actual engineering sampling analysis. The results show that when high chlorine solid waste returns to sintering, it has little influence on yield, quality indexes and metallurgical properties of the sintered ore, but it will lead to the increase of chlor-alkali dust, dioxin and hydrogen chloride emissions in sintering flue gas, accelerate the hardening and corrosion of the grate in sintering furnace and electric precipitator, and reduce the efficiency of electric precipitator. The increase of chlor-alkali dust, dioxin and hydrogen chloride will increase the burden of flue gas purification system, and result in the enrichment of chlorine.