A series of cotton samples with different humidity and temperature were analyzed by self-ignition method and TG-DTA. It was proved that thermal analysis method can represent the self-ignition process of cotton. The effect of humidity in cotton's degradation process was studied, and the 3 exothermic methods of cotton in the process were discussed. Furthermore, the thermal analysis curves were calculated by kinetics method. Results showed that the self-ignition temperature of cotton is 260~280 ℃ ; The initial decomposition temperature in air atmosphere is 20 ℃ earlier than that in nitrogen atmosphere, and the whole degradation process is different too; the self-ignition risk increases with the relative humidity, while the self-ignition temperature is still above 220 ℃ ; Mildew reaction is the main reason of. Self-ignition risk increasing.%对不同温、湿度状态的棉花进行自燃温度测定和差热—热重分析,证实了热分析实验对实际自燃过程的高度重现,考察相对湿度变化对棉花热分解过程的影响,分析棉花的三种放热方式在该过程中的贡献,并对热分析曲线进行动力学研究.实验结果表明,棉花的自燃温度为260～280℃；空气气氛中,起始分解温度比氮气气氛中的提前了20℃,整个分解过程也发生了变化；相对湿度增加,自燃风险增大,但自燃温度仍在220℃以上；霉变反应是自燃风险增大的主要原因.
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