Microplastics, as an emerging environmental pollutant in the 21^st century, have positioned their environmental fate and ecological risks at the forefront of global environmental science research. This study systematically analyzed the evolutionary trajectory, knowledge structure, and research frontiers of soil microplastic research, utilizing bibliometric tools VOSviewer and CiteSpace on literature data (2004—2024) from the Web of Science Core Collection and the China National Knowledge Infrastructure (CNKI) database. The results revealed three primary international research focuses: 1) Pollution characteristics, environmental behavior, and ecological-health effects of soil microplastics; 2) Source apportionment, multi-media transport, and quantitative detection/assessment systems for microplastic pollution; 3) Occurrence characteristics and migration control/remediation practices for regional soil microplastics. Burst detection analysis indicated a significant shift in international research focus post-2016, with keyword clusters transitioning from "marine environment" and "freshwater systems" towards "agricultural soil" and the "surface water-groundwater interface". Research dimensions have expanded from pollution characterization to encompass environmental process simulation and mechanistic analysis of biotoxicity. Domestic (Chinese) research exhibited distinct characteristics, evolving through three phases (2016—2019, 2020—2022, 2023—2024), demonstrated an overall trend shifting from theoretical framework construction towards the exploration of remediation technologies and control measures. Future research necessitates further elucidating microplastic-environment interfacial enrichment mechanisms, deciphering soil functional network response pathways, and establishing standardized detection-monitoring-remediation technical frameworks. This will provide systematic solutions for global soil microplastic pollution prevention and control.