Abstract: Humus composition characteristics of top soil in six counties from Henan, Anhui and Hunan of full flavor tobacco-growing regions were analyzed. The results were as follows: 1) Carbon content of humus (Hu-C) in full flavor tobacco-growing regions was 15.71 g/kg in average. Humic acid carbon content (HA-C), fulvic acid carbon content (FA-C) and humin carbon content (HM-C) were 3.87, 3.40 and 8.44 g/kg respectively. Coefficient of variation of every humus component was significant. 2) There were significant differences of humus composition between different soil types. The Hu-C content level of different soil types was as follows (from high to low): paddy soil > red soil > brown soil. The humification degree in paddy soil was the highest, and in red soil the lowest. 3) Humus and composition carbon contents in south Hunan were relatively high, and those of middle Henan relatively low. The soil HA/FA ratios of middle Henan and south Anhui were remarkably lower than south Hunan, three values of them were 0.92, 0.81 and 1.32 respectively. The soil humus activation degrees in south Hunan was remarkably lower.