Abstract:  The gasification experiments of co-gasification of biomass and petroleum coke were conducted in a fixed-bed reactor to determine the effect of the gasification mode, mix mode and proportion, particle size of petroleum coke on the tar yield and gas heat value, which was intended to provide the support for the idea of decoupled dual fluidized bed co-gasification of biomass and petroleum coke. The results show that the gas heat value decreases from 5.35MJ/m³ to 2.98MJ/m³ with the increasing of oxygen content from 2% to 15%. The average tar yield is 6.4%, and gas heat value is 4.31MJ/m³ as biomass is gasified alone at 700℃. For the co-gasification, the average tar yield is 2.9%, and gas heat value is 5.19MJ/m³. At the temperature of 700℃, the best ratio of the petroleum coke to biomass is 1∶1 as the oxygen content is 4%. The largest tar yield is produced for the gasification with petroleum coke alone, and the smallest tar yield for the co-gasification with feeding the petroleum coke first. With the increasing particle size of petroleum coke, the tar decomposition rate decreases gradually. The tar yield decreases with temperature for any case.