Abstract: The effects of gas temperature fluctuations on the soot inception and surface growth reactions as well as soot oxidation reactions are investigated.The results indicate that the instantaneous variations of soot mass fraction are influenced by the gas temperature fluctuation in both processes of soot inception and surface growth and soot oxidation under the time-averaged gas temperature of 1 500~1 800 K.The influences are enhanced by the increase in the fluctuation amplitude of the gas temperature.The gas temperature fluctuation results in faster rates of soot nucleation and surface growth reactions in the processes of soot inception and surface growth.The time-averaged soot mass fraction increases with the fluctuation amplitude of the gas temperature.While the increase in the fluctuation amplitude of the gas temperature leads to decrease in the time-averaged soot mass fraction and increase in the time-averaged soot particle number density during the processes of soot oxidation.