This paper summarized the coke passivation technology which was carried out by major domestic steel companies and research institutions.The paper briefly discussed the different knowledge on coke reactivity between different periods.The reaction in a blast furnace is extremely complex and it is a “black box”.As the level of awareness of different periods is various,the understanding is opposite. Furthermore,this paper also declared that the effects of temperature and CO_2 concentration of the reaction of coke with CO_2 were very significant through some tests that change CO_2 concentration and reaction temperature.The relationship between coke reaction loss rate and post-reaction strength were considered. After the factors that coke reacts with CO_2 in a blast furnace and in a laboratory were compared and analyzed,it was found that the reaction of coke with CO_2 under the standard test condition was very different from that with the blast furnace condition.Under the standard test conditions(at 1 100℃constant temperature and with 100%CO_2 for 2 h,the ash composition catalysis is exaggerated,but the factor of carbonaceous structure and porosity are weakend.The total weight loss of coke is unrestricted.In the blast furnace,coke goes through a heating-up reaction process,but the CO_2 concentration that is affected by the ore reduction performance is low,UPC replace part of direct reduction of carbon consumption that protect the coke,so total weight loss of coke is affected by degree of direct reduction and UPC rate. In view of the change reaction time test result and analysis of the passivation test result of reference,it was pointed out that the passivation only change the reaction rate of the coke with CO_2,therefore,the coke reaction loss rate was reduced in the fixed period,and the post-reaction strength of coke was increased,but in the blast furnace,it proved to be a heating-up reaction process of the fixed reaction loss rate and the mineral catalysis was ineffective,thus,we bring forward a discussion on the coke passivation technology. This paper summarized the coke passivation technology which was carried out by major domestic steel companies and research institutions. The paper briefly discusses the different knowledge on coke reactivity between different periods. The reaction in a blast furnace is extremely complex and it is a “black box ”. As the level of awareness of different periods is various, the understanding is opposite. furthermore, this paper also declared that the effects of temperature and CO_2 concentration of the reaction of coke with CO_2 were very significant through some tests that change CO_2 concentration and reaction temperature.The relationship between coke reaction loss rate and post-reaction strength were considered. after the factors that coke reacts with CO_2 in a blast furnace and in a laboratory were compared and analyzed, it was found that the reaction of coke with CO_2 under the standard test condition was very different from that with the blast furnace condition. Unit the standard test con ditions (at 1 100 ° C constant temperature and with 100% CO_2 for 2 h, the ash composition catalysis is exaggerated, but the factor of carbonaceous structure and porosity are weakend.The total weight loss of coke is unrestricted.In the blast furnace, coke goes through a heating-up reaction process, but the CO 2 concentration that is affected by the ore reduction performance is low, UPC replace part of direct reduction of carbon consumption that protect the coke, so total weight loss of coke is affected by degree of direct reduction and UPC rate. In view of the change reaction time test result and analysis of the passivation test result of reference, it was pointed out that the passivation only change the reaction rate of the coke with CO_2, therefore, the coke reaction loss rate was reduced in the fixed period, and the post-reaction strength of coke was increased, but in the blast furnace, it proved to be a heating-up reaction process of the fixed reaction loss rate and the mineral catalysis was ineff ective, thus, we bring forward a discussion on the coke passivation technology.