Abstract: The specific surface area and pore volume of partially gasified petroleum cokes of different conversions are determined. Change of pore structure of partially gasified petroleum coke and its relationship with the gasification rate are investigated. The results show that pores of petroleum coke are mainly micropores. The specific surface area and pore volume increase with carbon conversion during steam gasification. Gasification rate plots changes differently for petroleum coke with different porosity and surface area. The reactivity has a close relationship with pore structure. There is a good linear relation between the specific gasification rate and the effective specific surface area.