Abstract: Soil microplastic pollution has attracted wide attention. Due to the complexity of soil matrix, there is no standard method for extracting microplastics from soil. In order to explore the standard separation method of soil microplastics, the extraction effects of three different treatment methods of pre-digestion, post-digestion and pre-digestion and post-digestion on polyethylene (PE), polypropylene (PP), polystyrene (PS), polyamide resin (PA), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polylactic acid (PLA), polyhydroxyalkanoate (PHA) and polybutylene adipate (PBAT) in red soil, cinnamon soil and black soil were evaluated. The results show that the total recovery rate of microplastics in the three soils ranged from 96% to 102%. Considering the removal of matrix effect and the degree of damage to the target microplastics, the optimal digestion scheme is post-digestion of soil. The optimal soil microplastics extraction method is based on the microplastics separation device with saturated ZnCl₂ solution for 3 times density flotation, and then 5 μm aperture nitrocellulose filter membrane vacuum filtration, using 30% (w) H₂O₂ under the condition of 70 ℃ to digest and remove soil organic matter. After the completion of digestion, vacuum filtration is performed again. The organic matter in the soil can then be effectively removed while extracting microplastics.