The objective of this study was to investigate whether the effects of tobacco stalk biochar on the liable organic carbon of typical tobacco planting soil are consistent among different soil types.The experiments were conducted in two soil types in Bijie city，Guizhou province:yellow soil area(Qianxi Linquan Science and Technology Demonstration Park in the east) and yellow brown soil area(Weining Black Stone Science and Technology Demonstration Park in the west).The changes of soil total organic carbon(TOC)，readily oxidized organic carbon(ROOC)，dissolved organic carbon(DOC) and microbial biomass carbon(MBC) of rhizosphere and bulk soils under different biochar amendments(0，5，20，40 t·hm-2 denoted by B0，B5，B20，B40，respectively) were measured.After the application of biochar，the variation of TOC，ROOC and DOC in rhizosphere soil were consistent，while other organic carbon was inconsistent in the two soils. The overall trend was that the contents of TOC，ROOC and DOC had no significant change in B5 treatment，but increased significantly in B20 and B40 treatments.Compared with B0，the highest increases of the three organic carbon contents were 305.63%，630.41% and 768.48%，respectively.The peaks of different organic carbon and soil types appeared in B20 or B40 treatment.The content of MBC in bulk soil decreased significantly by 20% in yellow soil B5 treatment，and increased significantly by 53.98% and 145.80% in yellow brown soil B20 and B40 treatments，respectively.And there was no significant difference between other treatments and B0.In rhizosphere soil，MBC content increased significantly by 42.17% only in yellow soil B20 treatment，and there was no significant difference between other treatments and B0.The effects of short-term application of biochar on liable organic carbon components(especially MBC) in tobacco growing soil were related to soil type，biochar application rate，rhizosphere environment and so on.