The dual structure of surface erosion and underground leakage in karst areas results in complex runoff and sediment production processes; however, their influencing factors and dominant mechanisms are not yet clearly understood. Therefore, a quantitative synthesis was conducted on the relevant literature in karst areas of China, including 1323 sets of data from 63 related studies, to elucidate the distribution mechanisms governing surface soil loss and underground leakage in karst areas. The rainfall intensity, slope gradient, fissure degree, and bedrock exposure rate were influential factors. Random forest analysis showed that rainfall intensity was the most critical factor, followed by the bedrock exposure rate. At rainfall intensities of less than 60 mm/h (rainstorm), sediment was primarily lost through underground leakage; at intensities below 100 mm/h (heavy rainstorm), runoff was mainly characterized by underground flow. Consequently, sediment and runoff were more prone to underground leakage under low rainfall intensity (60 mm/h). On steep slopes (>20(degrees)), sediment and runoff were mainly lost through surface erosion. The proportion of sediment and runoff lost through underground leakage was directly proportional to the fissure degree. Loss of sediment and runoff peaked at a bedrock exposure rate of 30 %. These insights offer valuable scientific guidance for comprehending the migration mechanisms of soil erosion and offer a reference for the experimental design and improve the test scheme to optimize soil erosion research in karst areas.