Abstract: Microbially induced calcium carbonate precipitation (MICP) is an emerging soil reinforcement technology characterized by minimal construction disturbance, green and environmental friendliness. Biostimulated MICP approach achieves microbial mineralization and soil reinforcement by introducing a stimulation solution into the soil to enrich indigenous urease-producing bacteria in situ. This study investigates the effectiveness and mechanisms of biostimulated MICP technology in enhancing the resistance of soil slopes to rainfall erosion. Indoor slope model scour tests were conducted, incorporating different numbers of cementation treatments (0, 2, 4, 6, and 8 cycles) and cementation solution concentrations (0.5, 1.0, and 1.5 mol/L). Evaluation indicators included surface morphology changes, mass loss rate, and variations in the electrical conductivity and pH of the runoff. The results demonstrate that the biostimulated MICP treatment significantly reduces soil erosion by forming a dense protective layer on the slope surface, primarily through calcium carbonate cementation and pore-filling effects. For the same number of treatments, a cementation solution concentration of 1.0 mol/L yielded the optimal erosion resistance, while higher concentrations did not yield additional improvements. The findings confirm the feasibility of applying bio-stimulated MICP technology to earth slope protection engineering and provide an important reference for addressing slope erosion issues through this method.