The role KOH in the one-stage KOH-activation of rice straws was studies using FTIR, XPS,TGA, and DTG techniques. It was found that at the impergnation, KOH extracts to some extent the lignin componrent from rice straw and reats with hydroxyl groups. On heat-treatment, the impregnated KOH facilitastes intermolecular condensation reaction on one hand but retards the thermal degradation of cellulos molecules on the other hand.