Two kinds of coke were chosen to study the reaction characteristics with CO2,pellet and lump ore, i.e.coke A represents low CRI coke and coke B for high CRI coke.The reasons for the difference of coke reactivity are discussed from perspective of heat absorption.The results show that high reactivity coke B is easier to react with CO2,pellet and lump ore than low reactivity coke A.When the carbon atoms of low reactivity coke separate from the molecular structure,more energy is consumed.More energy is needed to absorb so as to break the molecular structure and trigger chemical reaction.The energy consumption of high reactivity coke B is low,carbon atoms are easier to separate from coke moleculars.As a result,this chemical reaction is characterized with low temperature and uniform reaction.