【Objective】 Land reclamation is a significantly important way to restore soil productivity in high groundwater mining areas. However, most of the reclaimed soil always shows poor functions, such as lower fertility and biodiversity, while the in-depth understanding of microbiological mechanisms underlying the formation and restoration of multifunctional reclaimed soil is still deficient. 【Method】 Four reclamation plots including 9 years, 12 years, 15 years, and 18 years of reclamation, and 1 control plot from the Dongtan mining area in Zoucheng City, Shandong Province, were selected as the research objects. A total of 75 surface soil samples were collected, and 18 soil physical, chemical, and biological indicators such as organic carbon were measured to explore the interaction between soil microbial communities and soil multifunctionality, as well as the microbiological mechanisms of multifunctionality variation. Moreover, based on the molecular ecological network methods, supplemented by statistical analysis methods, several microbial networks were constructed to investigate the interaction between microbial community diversity, network structure, and soil multifunctionality. 【Result】 The results showed that: (1) Land reclamation activities and the normal vegetation rotation of the cultivated land have significantly improved soil multifunctionality, with soil multifunctionality almost reaching the undisturbed control level after 18 years of reclamation. Moreover, among the soil properties, soil organic carbon, pH, available phosphorous, and most enzyme activities were important influencing factors for multifunctionality. (2) With the increasing reclamation years, soil microbial diversity significantly increased, while the richness performance of bacteria and fungi was different. The increasing trend of bacteria was not significant after 12 years of reclamation whereas fungi increased significantly until 18 years of reclamation. However, the abundance of bacteria and fungi reached normal farmland levels after 15 years and 18 years of reclamation, respectively. (3) The analysis results of the microbial co-occurrence network showed that the nodes, edges, average degree, average path length, network density, clustering coefficient, and betweenness centrality in the bacterial community co-occurrence network significantly increased with the increase of reclamation time. Moreover, the topological properties of bacterial and fungal subnetworks such as edge, degree, and network density were significantly positively correlated with soil multifunctional properties. The diversity of microbial communities showed a positive impact on the network complexity, enhancing the association between species and thereby enhancing their versatility. Both the complexities of bacterial and fungal community networks presented significant correlations with soil multifunctionality. The impact of bacterial network complexity on soil multifunctionality was not affected by other indicators, whereas the correlation between fungal network complexity and soil multifunctionality was influenced by bacterial richness, soil microbial diversity, and fungal richness. The structural equation model results indicated that microbial diversity can directly and positively regulate soil multifunctionality, or indirectly manipulate soil multifunctionality by positively influencing the network complexity of bacteria and fungi. 【Conclusion】 This study has revealed the driving mechanism of multifunctional restoration of reclaimed soil in the eastern plain mining area, which would provide important guidance for the deeper understanding of the development and functional succession of reclaimed soil microbiota, as well as soil quality management and protection.