In this study, a pyrolysis-gas chromatography/mass spectrometry method was established to quantify microplastics (MPs) released from plastic food containers during rinsing and migration. The inner surface of actual samples was rinsed with deionized water, and the MPs in rinse water were collected through a glass fiber membrane with pore size of 1 μm. Subsequently, thoroughly cleaned polypropylene (PP) food packaging containers were selected for migration tests under different simulants, migration temperatures, and migration times. It was found that MPs corresponding to the materials of product manufacture were detected in all collected containers during rinsing. By migration tests, the results showed that high-fat foods, high/low temperature (5 °C), and long exposure periods can promote the release of MPs. It was also proved that the migration of MPs from plastic food containers was one of the important sources for human exposure to MPs. The obtained results can provide evidence for the safety risk assessment of plastic food containers.