In the present study, the chemical composition of water extracts of Chinese and Vietnamese cassia (Cinnamomum cassia) were compared using multivariate analysis of LC-MS data. By principal component analysis of the LC-MS data, 6 compounds, cinnzeylanine (1), cinnzeylanol (2), anhydrocinnzeylanol (3), cinncasinol A (4), epicatechin (5) and procyanidin B2 (6), were identified as the marker compounds to characterize Chinese and Vietnamese cassia. It was clarified that Chinese cassia contains relatively larger amounts of epicatechin and procyanidin B2. On the other hand, Vietnamese cassia is characterized by a relatively larger amount of diterpenes. As catechin derivatives and diterpenes have different types of activity, it is important to choose the cassia that best suits the product for which it is to be used, whether in food or in herbal medicine.