Cotton straw and stalk were thermo-chemically processed by fast pyrolysis under different conditions in a fixed tubular reactor. Fast pyrolysis studies were carried out under sweeping gas atmosphere in two groups. The effects of pyrolysis temperature, heating rate, and sweep-gas rate were investigated in the experiments. The highest yield, 39.51%, was obtained at 550degreesC final temperature, with heating and sweep-gas rates of 550 Kmin(-1) and 200 cm(3) min(-1), respectively. The pyrolysis products and the subfractions of pentane soluble were characterized by elemental analysis, gas chromatography, IR spectroscopy, and H-1-NMR spectroscopy.