In this study, a simple, rapid and sensitive method for the determination of 20 phthalate esters (PAEs) in fatty food by UHPLC–MS/MS has been developed. Samples were pretreated by an SPE method, using the ProElut GLASS PSA (1000 mg / 6 mL), which is made for the determination of PAEs in food. The standard calibration curves were linear for all the analytes over the concentration range of 10–50 ng mL⁻¹, and the correlation coefficients ranged from 0.9992 to 0.9999. The LODs and LOQs were in the ranges of 0.02–1.6 μg kg⁻¹ and 0.06–5.2 μg kg⁻¹, respectively. The accuracy of this method was evaluated by measuring the recovery from spiked samples. The recoveries of all 20 phthalates from samples spiked at three different concentrations (10, 20, and 50 ng mL⁻¹) were determined, the recovery ranges in low, intermediate and high spiked levels were 80.9–119.7%, 84.5–121.0% and 85.5–121.5%, respectively, and the RSD range of the recovery results (n = 6) was 1.0–11.7%. We also investigated the migration of PAEs, the research results indicated that PAEs could migrate from both plastic and paper bags to foodstuff, and heating could accelerate the migration.