Abstract: Using CO2 as the gasification agent, the gasification reactivity of the petroleum coke and the mixtures with Houbulian coal chars was studied in a self-made tubular reactor under normal pressure and at temperature ranging from 1 200 ℃ to 1 500 ℃. The difference of carbon structure ordering between petroleum coke and coal char processed at high temperature was analyzed by using XRD. The results show that the gasification rate of petroleum coke decreases rapidly when the carbon conversion rate is higher than 70% and the gasification temperature is over 1 300 ℃. The higher the gasification temperature is, the faster the gasification rate of petroleum coke declines. The gasification reactivity of the mixture of petroleum and coal char is different from that of pure petroleum coke or pure coal char. With the variation of the ratio of petroleum coke to coal char, the inflexion varies because of the different reactivity between petroleum coke and coal char. With the increase of gasification temperature, the decrease of gasification rate of the petroleum coke results in the appearing of inflexion at higher carbon conversion. The XRD test indicates that after being handled at high temperature, the degree of carbon structure ordering in petroleum coke is greater than that in coal char. The carbon structure ordering obviously at high temperature is an important reason to lead to the sharp reduction of petroleum coke gasification rate.