Numerical analysis is performed to investigate the influences of gas temperature fluctuation on soot formation and oxidation. The gas flow has a time-averaged gas temperature of 1400-1700 K. The instantaneous variations of soot volume fraction with time are obtained under different conditions. Obvious differences are found between the results with and without the gas temperature fluctuation. The time-averaged soot volume fraction decreases with the fluctuation amplitude of the gas temperature. The evident influences of the gas temperature fluctuation on the reaction processes of soot formation and oxidation are thus delineated. (C) 2013 Elsevier Ltd. All rights reserved.