In order to reveal the difference of soil infiltration characteristics between exposed rock-soil interface and non-rock-soil interface in karst rocky desertification area, the ring knife method was used to explore the soil infiltration characteristics of rock-soil interface and non-rock-soil interface, as well as the adaptability of infiltration model. The results showed that: (1) The bulk density of 0—10 cm soil layer and 10—20 cm soil layer soil at rock-soil interface was higher than that at non-rock-soil interface, while the total soil porosity was lower than that at non-rock-soil interface. The water content and capillary porosity of rock-soil interface was generally greater than that of non-rock-soil interface, while non-capillary porosity, clay particles and drainage capacity was generally less than that of non-rock-soil interface. (2) The infiltration capacity of rock-soil interface was generally less than that of non-rock-soil interface, and the initial infiltration rate, average infiltration rate and stable infiltration rate at rock-soil interface was lower than that at non-rock-soil interface (except flat). (3) The initial infiltration rate, average infiltration rate and stable infiltration rate of the 0—10 cm soil layer and 10—20 cm soil layer of the three shapes at rock-soil interface followed the order of flat > convex > concave. The infiltration at non-rock-soil interface was similar to that at rock-soil interface, which was mainly determined by soil bulk density and total porosity. (4) The fitting effects of Horton model on soil infiltration at rock-soil interface and non-rock-soil interface were better than Kostiakov model and Philip model, and it could better simulate soil infiltration characteristics under complex conditions in karst areas. This study was expected to provide new research ideas and scientific theoretical support for the in-depth understanding of water infiltration and soil erosion in karst areas.