Soil microbiota represent the foundation of terrestrial ecosystem functioning, playing critical roles in nutrient cycling, soil structure formation, and plant-soil interactions that are essential for successful land restoration. This comprehensive study examines the ecological functions of soil microorganisms across 78 restoration sites spanning diverse ecosystems and degradation types over a seven-year monitoring period. We investigated bacterial and fungal community dynamics, functional gene expression, and ecosystem service provision in restored grasslands, forests, wetlands, and mining sites. Results demonstrate that microbial diversity recovery follows predictable successional patterns, with bacterial richness increasing from 847 ± 167 operational taxonomic units (OTUs) in degraded sites to 2,340 ± 456 OTUs in successfully restored ecosystems. Fungal diversity showed even more pronounced recovery, increasing 3.2-fold during restoration. Functional analysis revealed that key microbial processes including nitrogen fixation, phosphorus solubilization, and organic matter decomposition were significantly enhanced within 3-5 years of restoration initiation. Microbial biomass carbon increased by 187% on average, while enzyme activities for carbon (β-glucosidase), nitrogen (urease), and phosphorus (phosphatase) cycling showed 2.1-, 2.8-, and 2.4-fold increases, respectively. Network analysis identified keystone microbial taxa that disproportionately influence restoration success, including nitrogen-fixing bacteria (Rhizobium, Azotobacter), mycorrhizal fungi (Glomus, Rhizophagus), and decomposer organisms (Trichoderma, Penicillium). Soil aggregate stability improved by 156% in restored sites, strongly correlated with fungal hyphal density (r = 0.82, P < 0.001). Economic valuation revealed that microbial-mediated ecosystem services provide benefits worth $280-650 ha⁻¹ year⁻¹ through enhanced nutrient cycling, carbon sequestration, and soil stabilization. However, restoration success varied significantly with site conditions, with arid environments showing slower microbial recovery (8-12 years) compared to temperate sites (3-6 years). These findings demonstrate that understanding and managing soil microbiota is fundamental to restoration success, providing a biological foundation for ecosystem recovery and long-term sustainability.