To establish a method for the determination of characteristic ion mass spectrometry of Eupolyphaga Steleophaga,to identify the authenticity of Eupolyphaga Steleophaga and its preparations,and to evaluate the quality of the medicinal materials and preparations of Eupolyphaga Steleophaga in the market. Ultra-performance liquid chromatography-triple quadrupole mass spectrometry was used to detect the medicinal materials and preparations of Eupolyphaga Steleophaga.m/z 415.72 (double charge) → 406.72 (double charge) and 415.72 (double charge) → 667.34 were used as detection ion pairs.The ion-pair chromatographic peak could be detected in 24 batches of Eupolyphaga Steleophaga of different origins,21 batches of Eupolyphaga Steleophaga extract and six batches of square preparations.However,the corresponding chromatographic peaks were not detected in six batches of different animal drugs or three batches of its adulterants.The method established in this study effectively supplements the deficiencies in the inspection standards of Eupolyphaga Steleophaga,improves its quality control level,and provides a reference for the safety and efficacy of clinical use of Eupolyphaga Steleophaga related drugs.