【Objective】 A large amount of plastic waste is produced globally every year, and landfill is the most common way to deal with plastic waste. However, plastic waste that enters landfills will continuously generate microplastics under the influence of physical, chemical, and biological factors, thereby affecting the surrounding ecological environment and human health.【Method】 In this study, the occurrence characteristics of microplastics in the soil-groundwater system of a landfill in Taizhou, Zhejiang Province, were investigated, and the ecological risk of microplastics in this area was assessed by pollution load index (PLI), polymer risk index (H), and potential ecological risk index (PERI). 【Result】 The results showed that the abundance of microplastics was 28313±7687 microplastics/kg, 7789±585 microplastics/L, 25660±2614 microplastics/kg, 183±41 microplastics/L in landfill, leachate, soil, and groundwater, respectively. The microplastics were mainly thin film and of a small size (0-50 μm). Also, the polymer composition was mainly polyethylene (PE) and polypropylene (PP). In addition, the microplastic ecological risks of the landfill""s waste, soil, leachate, and groundwater were respectively at extremely high risk, high risk, high risk, and medium risk. 【Conclusion】 Landfill sites, as an important source of microplastics, have potential impacts on the surrounding environment. This study can provide theoretical support for the assessment and control of microplastic pollution in the soil-groundwater system of landfill sites.