The combustibility of the cut tobacco under different relative humidity（RH） was investigated by simultaneous thermal analysis.The results showed that:①The moisture content of cut tobacco increased with the increase of RH，and there was a linear correlation between the moisture content and RH.②By comparing the weight loss rate of every stage，different moisture contents of the cut tobacco had effect on their combustion reaction and pyrolysis reaction.Between 50% and 60% of the RH，there was a turning point where the major trend of weight loss rate varied.③The combustion characteristics of cut tobacco were decreased with the increase of RH，RH was significantly correlated with the moisture content of cut tobacco and the average rate of combustion.The moisture content of cut tobacco was negatively significantly correlated with the ignition temperature.However，RH had no significant correlation with the combustion characteristics.