Abstract: Microbially induced carbonate precipitation (MICP) technology shows great potential for ecological slope restoration due to its excellent cementation and environmental compatibility. However, MICP-treated soil often suffers from poor plant adaptability and lacks systematic evaluation indices for mix design. To address these issues, a multivariate orthogonal experiment was conducted based on plant adaptability and soil erosion resistance. Key factors including plant species, cementation solution concentration, bacterial OD value, pre-cultivation period, compacted dry density, and initial moisture content were selected. Plant survival rate and sample disintegration rate were taken as evaluation indicators, and the TOPSIS method was adopted for comprehensive assessment. The results show that the sensitivity of the factors to the overall performance follows the order: plant species &gt; initial moisture content &gt; pre-cultivation period &gt; compacted dry density &gt; cementation concentration &gt; bacterial OD value. The optimal combination (ryegrass, 20% initial moisture content, 10 d pre-cultivation, 1.5 g/cm³ dry density, 0.1 mol/L cementation solution, OD=1.0) achieves the highest relative closeness ( <italic>C</italic>_i=0.7469) and excellent slaking resistance. Appropriate MICP treatment not only ensures root respiration and growth, but also induces calcite crystals to form a “bio-mineral” synergistic reinforcement with the root network, significantly improving soil hydro-stability. The experimental and collaborative optimization method proposed in this study can provide a reference for parameter selection in MICP-based ecological slope protection projects.