The large-scale use of plastic products has caused the increasing content of microplastics (MPs) in soils, which has attracted extensive attention. At present, the main factor that obstructs the assessment of soil environmental ecological risk is the lack of standardized testing and quantitative methods. However, the detection methods of MPs in complex soil media were still not homogeneous, which seriously affected the comparability and reliability of the previous studies. In this study, the microwave digestion method was used to extract MPs at once from complex soil media by optimizing the microwave digestion conditions (acid system, the heating procedure and the amount of acid added). The results showed that 0.1 g soil could be completely microwave digested by 15 mL HCl + 5 mL HNO₃ + 3 mL HF, and MPs could be completely extracted from the soil. Besides, the extraction efficiencies of polystyrene (PS), polyethylene (PE), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA) and polypropylene (PP) in the scaling experiment were 126%, 146%, 51%, 85%, 96% and 162%, respectively. The weight of plastics (PS, PE and PP) was increased after digestion, possibly because the physical and chemical reaction between acids and MPs could change the surface properties of MPs, resulting in the higher porosity of MPs. The adsorption capacity of metals and organic matters were increased. However, the extraction efficiency of PMMA and PVC was above 80% under the condition. All plastic particles showed the degradation in the microwave digestion through the analysis of plastic surface morphology, but the results of Fourier infrared conversion spectroscopy (FTIR) showed that microwave digestion did not affect the identification of plastic types. However, the current method is only be applicable to qualitative and preliminary quantitative analysis, standardized quantitative analysis needs to be further explored.