Abstract: A direct carbon fuel cell (DCFC) was assembled with yttria stabilized zirconia (YSZ) as electrolyte and active carbon (AC), graphite (G) and semi-coke (SC) were employed as the DCFC fuels. The influences of the carbon fuel pore structure and reactivity, operation temperature, anode atmosphere on the anode reaction were investigated. The results indicated that for three carbonaceous fuels, the performance of DCFC is in the order of AC > SC > G, the same as that for their oxidation reactivity in air or CO₂ atmosphere. The reactivity of carbonaceous fuels is determined by their surface oxygenic functional groups and pore structure. Moreover, the results revealed that the DCFC anodic reactions involves the oxidation of C to CO₂, the conversion of CO₂ to CO via the reverse Boudouard reaction, and the oxidation of CO to CO₂.