Abstract: In order to study the source of typical gelatin in different types of Ejiao products, nine common Ejiao products on the market including three kinds of Ejiao cake, Ejiao oral liquid and Ejiao granule, were selected as the research objects. Moreover, 1% bovine gelatin and porcine gelatin were added in Ejiao products, respectively. High-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) was used to identify the characteristic peptides of typical gelatin including donkey gelatin, bovine gelatin, and porcine gelatin. The results showed that different characteristic peptides of typical gelatin were detected in nine kinds of Ejiao products. Through further analysis, it was found that the common characteristic peptides of donkey gelatin, bovine gelatin, and porcine gelatin shared by these 9 Ejiao products were 25, 3, and 14, respectively, where the unmodified characteristic peptides were 7, 2, and 3 in turn. Among them, 22, 2, and 5 common characteristic peptides were derived from the α₁ chain, respectively. Meanwhile, 3, 1, and 9 common characteristic peptides were derived from the α₂ chain, respectively. These common characteristic peptides could be used as the basis for the identification of gelatin sources in complex systems by HPLC-MS/MS, and give guiding significance in gelatin identification for different Ejiao products.