Abstract: Dendrogeomorphological method was used to study soil erosion in two typical karst sites (Puding and Zhengfeng) in Guizhou Province, China. Eleven pairs of exposed and unexposed tree roots were measured in the field and sampled for anatomical characteristics. The results showed that the exposed roots recorded karst soil erosion. Significant changes were shown in the anatomical characteristics of the exposed tree roots when soil erosion occurred, such as suddenly narrower tree rings, smaller cells, and fewer earlywood cells. Meanwhile, the fabre lumen and vessel lumen areas markedly declined to the range of 39.20% to 70.66%, which only slightly implies soil erosion. The accurate time period during which soil erosion occurred was identified and combined with the age of the tree roots. Dynamics of soil erosion were calculated and soil erosion recorded by the exposed roots from 2002 to 2007 at an average rate of 0.484 t y-1 at Puding, and from 2005 to 2007 at an average rate of 0.051 t y-1 at Zhenfeng. Karst soil erosion was recorded by not only one species but by multi species of broadleaf tree roots, which can significantly enhance the study of karst soil erosion through the use of Dendrogeomorphological method. The quantity of eroded soil was found to be extremely large when records from the exposed tree roots were compared with estimates from site measurements of runoff. The major type of karst soil erosion was underground soil loss and this comprised approximately 2/3 of total erosion.