The process of karst soil formation lies in the decrease of C, Ca, Mg and accumulation of Fe, Mn, Cu, Pb, Zn and acid indissoluble substance. The biomass carbon is vast at the experimental site. Experiments show that plant remnant is rapidly decomposed in the first season after bury and hence releases a large volume of CO2to take part in karstification. The organic carbon content of soil (SOC) is great, and SOC is preserved in large quanitites. Loosely combined SOC content of surface material, slope and saddle soil is high, serving as the potential source of karst CO2. SOC may be oxidized by acid solution (KMnO4solution). SOC in LayerA is more easily oxidized than that in Layer B. The field monitoring experimental study on CO2in soil and its emission rate suggests that karstification is more active under the humid weater condition. The characteristics of C13indicate that SOC is the main source of soil CO2, and soil CO2 is an important source of karst spring HCO-3. The experiments on relationships of soil, organic matter and limestone dissolution reveal that karstification is obviously stimulated by soil and organic matter. Karst is better developed in humid season and in slope.