The removal mechanisms for main pollutants in sintering flue gas, process flow for flue gas purification and systematical equipment of the sintering flue gas purifying systems by activated coke were introduced in detail, which is the first two-stage purifying system of its kind in China. The major facilities including flue system, adsorption system, desorption system, activated coke storage and transportation system were systematically and completely illustrated. The inner structure, working principle, and relevant designing and operating parameters of some major equipment were concisely presented. The technological characteristics of this purifying system were summarized, and the actual treatment effect was presented. The results showed that, this system has the advantages of high reduction rate of pollutants and steady and reliable operating performance. The average SO₂ content in sintering flue gas is 430.5 mg/Nm³ before being purified, while its content is decreased between 0.224 and 4.203 mg/Nm³ after treatment, with a high removal rate from 99.02% to 99.95%; the average NO_x content is 277.5 mg/Nm³ before being purified, while its content is decreased between 20.9 and 41.5 mg/Nm³ after treatment, with a removal rate from 85.05% to 92.47%; the average toxic equivalent quantity of dioxin is decreased to 0.0484 ngTEQ/Nm³ after treatment; the dust content after treatment is decreased between 14.0 and 14.7 mg/Nm³. Compared with one-stage adsorption purifying system, two-stage purifying system can deeply reduce SO₂ and significantly improve the removal rate of NO_x. An evaluating conclusion on this two-stage purifying system was drawn based on the actual treatment effect and practical run performance. Meanwhile, the application prospect of this new purifying system was predicted.