Abstract: TG and DTG experiments were carried out to study the pyrolysis kinetic behavior of the southern fir in various conditions. The atmosphere was changed from air to nitrogen or from nitrogen to air when the sample was heated to 200 ℃, 300 ℃, 400 ℃ and 500 ℃ respectively in a series of experiments. The aims of these experiments were to simulate the cases of local poor oxygen caused by fire and rich oxygen caused by the fresh airflow. The sample was first heated to 250 ℃, 300 ℃, 350 ℃, 400 ℃ and 450 ℃ respectively and then cooled to 50 ℃ and reheated to 700 ℃ in the atmosphere of air to simulate the repetitive burning after insufficient combustion in a fire. Through the experiments, the effects of pyrolysis conditions on the pyrolysis characteristics are understood. Based on the “First Order Two-stage Model”, the apparent activation energy and frequency factor of the samples in two temperature ranges of233.3 ℃～369.9 ℃ and 369.9 ℃～490.8 ℃ were obtained, which are 77.85 kJ·mol－1 and 1.95×106s－1, and 138.18 kJ·mol－1 and 4.84×109s－1, respectively.