Abstract: In order to investigate the steam gasification characteristics of petroleum coke, the effect of coke particle size, water vapor flow rate, temperature, pressure and oxygen content on the steam gasification of coke was studied in a fixed bed gasification reactor. The results show that, when the petroleum coke particle size is smaller than 380 μm and more than 96 μm, and the steam flow rate is in a range of 0.85—4.60 g/min, the effect of internal and external diffusion on the steam gasification of petroleum coke reaction are essentially eliminated. On the premise of elimination of the influence of internal and external diffusion, the gasification reaction rate of petroleum coke presents the increased trend with the reaction temperature and pressure increasing. The influence of temperature on petroleum coke gasification rate is much larger. It is displayed that the content of H2 is decreased while the content of CO is increased. When oxygen is added to the reaction system, petroleum coke not only gives off heat with petroleum coke burning but also reacts with generated hydrogen and carbon monoxide, which has a huge influence on the reaction conditions and product distribution. Therefore, to ensure the gasification reaction quickly and efficiently, optimizing reaction conditions and developing supporting equipment are highly desirable.