[Objective] Soil erosion control has long been a research focus in soil and water conservation, and the integration of multiple methods represents a current hotspot. This study analyzes the synergistic effects of vegetation and Microbial-Induced Carbonate Precipitation (MICP), aiming to reveal the effectiveness of this combined approach for slope protection and its impact on hydrological and soil erosion processes, thereby providing new insights and technologies for slope soil erosion control. [Methods] This study conducted five groups of experiments, including a bare soil control group (CK), an MICP treatment group (MR), and three plants (Festuca Arundinacea FA, Medicago Sativa MS, and Chrysopogon Zizanioides CZ) respectively in combination with MICP for protective measures (FA-MC, MS-MC, CZ-MC). Based on a surface water-groundwater coupled model, a soil erosion model was constructed to quantitatively analyze soil erosion rates under these different slope protection designs. Techniques including direct shear tests, microscopic observation, and scanning electron microscopy (SEM) were utilized to comprehensively analyze the variations and underlying mechanisms of cohesion (c) and the internal friction angle (φ). [Results] The results demonstrated that: (1) The MICP treatment effectively cemented loose soil particles by filling soil pores with flaky and flocculent CaCO? precipitates, leading to a significant increase in the c value. It also reduced porosity and increased surface roughness, resulting in a higher φ value. The synergistic action of vegetation and MICP further enhanced both c and φ, with maximum increases of 402.81% and 33.91%, respectively, compared to the CK group. (2) The numerical model effectively simulated the runoff volume and soil erosion rate across the five experimental groups (with maximum mean absolute errors of 2.39×10?? m/s and 1.77×10?2 g/m2/s, respectively), providing a useful tool for analyzing hydrological and soil erosion processes under the synergistic effects of vegetation and MICP. (3) The synergistic effect of plants and Microbially Induced Calcite Precipitation (MICP) can not only significantly enhance soil strength but also improve soil permeability and water retention capacity. Moreover, through multiple erosion?reduction mechanisms (including plant interception and energy dissipation, water storage and flow diversion, and runoff interception), this synergistic system delivers integrated benefits of soil reinforcement, water conservation, and erosion mitigation. [Conclusions] The synergistic effect of plant and MICP could improve soil properties and reduce rainfall splash erosion and erosion on slope, thereby regulating soil erosion process. The developed numerical model can serve as an important tool for analyzing the soil and water conservation performance of different slope protection designs during soil erosion research.