OBJECTIVE： To provide reference for quality evaluation of Ejiao. METHODS： The contents of 17 amino acids in 18 batches of Ejiao from 18 manufacturers were analyzed by automatic amino acid analyzer； the content data was processed by principal component analysis （PCA） and hierarchical clustering analysis （HCA）， in order to understand the relationship among these amino acids and categorize the Ejiao products. RESULTS： Except for a batch of Ejiao， the other 17 batches contained 17 various amino acids， including 7 necessary amino acids （Thr， Val， Met， Ile， Leu， Phe and Lys） for human being， especially the contents of Gly and Pro were higher. The total content of amino acids was arranged from 66.1％ to 82.0％， showing great difference. Four main components were extracted by PCA， the cumulative contribution of which was 89.578％， and accordingly it may be considered that Pro， Ala， Glu， Asp， Leu， Ile and Thr were characteristic amino acids of Ejiao products. In hierarchical clustering analysis， 3 tree figures of commercial Ejiao product were achieved and Euclidean distance was varied among 0-25. CONCLUSIONS： There is great difference in total control of amino acid in commercial Ejiao product； Ejiao products from various manufacturers differ in their amino acid contents. Ejiao is rich in collagen， and therefore， using amino acid determination would be helpful to monitor its quality.