Abstract: Background In karst slopes of southwest China, soils exhibit a discontinuous, patchy distribution interspersed with carbonate bedrock. The outcropping carbonate bedrock not only contributes to the formation of soil‒rock interface cracks but may also enhance the development of soil desiccation cracks, which can significantly influence water infiltration. Nevertheless, due to practical constraints, such as large dimensions of bedrock and the challenge of effectively sealing field infiltration devices that need to cover both rock and soil, systematic understanding of how outcropping bedrock and cracks affect water infiltration parameters remains limited. Methods In this study, large carbonate rocks (height > 20 cm and long diameter < 45 cm) and lime soil were collected in the field. These materials were then assembled to six carbonate rock-soil masses with varying bedrock exposure ratios (13.0%、15.8%、17.1%、19.6%、32.5%、36.2%) and one pure soil mass (20 cm in height and 48 cm in diameter) as a control. To ensure stable development of the cracks, all test masses were subjected to three wetting and drying cycles. Then digital image processing and one-dimensional constant head vertical infiltration method were used to analyze the effects of outcropping bedrock on crack development and water infiltration. Results Results showed that the soil-rock interface cracks developed around all the bedrock, further promoting the formation of soil desiccation cracks. As the bedrock exposure ratio increased, the surface area and volume of soil-rock interface cracks increased significantly (p＜0.01), and the surface area of soil desiccation cracks increased significantly (p＜0.05). The total crack surface area ratio and volume ratio increased to 1.9-3.0 and 3.7-6.2 times those of the control. When the bedrock exposure ratio increased from 13.0% to 36.2%, the initial infiltration rate increased to 2.7, 3.2, 1.8, 1.8, 3.0, 2.7 times that of the control and was significantly positively correlated with the soil desiccation cracks volume (p＜0.01). The time to reach stable infiltration increased to 4.1, 10.1, 2.8, 3.6, 9.8, 3.3 times that of the control and was significantly positively correlated with the soil desiccation cracks volume (p＜0.05). Due to the relatively impermeable nature of carbonate rock, the stable infiltration rate decreased to 30%-60% that of the control and was significantly negatively correlated with the soil-rock interface crack length (p＜0.05). The Horton model provided a better fit for the water infiltration process in cracked rock-soil mass (R² = 0.75-0.96) than Kostiakov-Lewis model (R² = 0.55-0.83). Horton-k parameter showed significant negative correlation with the total crack surface area ratio and volume ratio (p＜0.05). Calibrating Horton-k parameter by incorporating these two ratios may enhance the Horton model accuracy for water infiltration simulation in cracked rock-soil masses. Conclusions This study indicates that outcropping carbonate bedrock enhances the development of soil-rock interface and desiccation cracks, and improves the infiltration capacity of plots over a certain period. The findings may offer scientific references for elucidating the mechanisms and precisely modelling the infiltration processes in karst regions.