In karst rocky desertification areas, epilithic mosses on exposed rock surfaces regulate the redistribution of rock surface flow by intercepting rainfall and altering flow pathways and velocities. To investigate the combined effects of moss cover on rock and slope surfaces on downstream soil erosion, 24 rainfall simulation experiments, namely 2, (degree of moss coverage on rock surfaces: 0 % and 100 %) x 4 (degree of moss coverage on slope surfaces: 0 %, 25 %, 50 %, and 75 %) x 3 (rainfall intensity: 60, 80, and 100 mm h- 1) experiments, were designed. The results indicated that moss cover effectively suppressed runoff generation during the 30 min by increasing surface roughness and water retention levels. At rainfall intensities of 60 and 80 mm h- 1, the mean sediment loss (SLmean) on the moss-covered rock surfaces decreased by 18.21 % and 25.62 %, respectively. However, at 100 mm h- 1, SLmean increased by 53.83 %, indicating trend reversal. Increasing moss coverage on slope surfaces consistently decreased SLmean, with a maximum reduction of 89.74 %. When slope moss coverage reached 75 %, the selective transport of sand particles by runoff increased. Furthermore, significant exponential relationships were observed among the hydrodynamic parameters, sediment loss (SL), and rainfall intensity, with shear stress (tau) identified as the most reliable predictor of SL. This study elucidates the dual role of epilithic mosses in erosion regulation, catalyzing a paradigm shift in rocky desertification management from soildependent to lithophyte biota utilization. These insights have broader implications for restoration in rocky mountainous ecosystems where edaphic constraints limit conventional revegetation approaches.