Karst rocky desertification is an important ecological issue hindering the socioeconomic development of the South China Karst region. In the present study, firstly, three typical rocky desertification regions-Bijie Yachi, Qingzhen Hongfenghu, and Guanling Huajiang, Guizhou Province, representing three different typical karst landforms-plateau mountain, plateau basin, and plateau gorge, respectively, were selected as experimental areas. Then, 90 sample plots with an area of 20 m×20 m each were established. The distribution of soil organic carbon (SOC) in relation to environmental factors (degree of rocky desertification, landform, vegetation, soil property, etc.) in these plots was determined using field measurements, laboratory detection, and mathematical statistics. The following results were obtained:1) The SOC content of karst rocky desertification ecosystems was low. The average content of the three experimental areas of Bijie Yachi (Plateau Mountain), Qingzhen Hongfenghu (Plateau Basin), and Guanling Huajiang (Plateau Gorge) was 23.42, 25.78, 26.03 g/kg, respectively. There was no significant (P=0.23) difference of SOC contents among the three different landform experimental areas. 2) Land cover change can affect the SOC content. The SOC content of virgin forest (31.32 g/kg) was the highest. With increased soil degeneration from virgin forest to gravel land, the SOC content first decreased and then increased. 3) The SOC content was correlated with soil physico-chemical properties. Specifically, the SOC content was extremely significantly positively correlated with total nitrogen content, hydrolyzed nitrogen content, available potassium content, total porosity, total phosphorus content, natural moisture capacity, field moisture capacity, capillary moisture capacity, and upper strata saturated permeability; significantly positively correlated with total phosphorus content and lower strata saturated permeability, and extremely significantly negatively correlated with soil bulk density. 4) The SOC content and plant diversity rich (R) and diversity (H) indices were extremely positively correlated. 5) There were significant differences of SOC contents between different degrees of rocky desertification. Along with increased degrees of rocky desertification, the SOC content initially decreased and then increased. Based on these results, the distribution pattern of the SOC content and its impact factors in karst rocky desertification ecosystems was clarified. These results have important implications for the protection of karst forest ecosystems, the reconstruction of rocky desertification ecosystems, and the response to global climate change.