A simple and efficient flow injection mass spectrometric (FIMS) method was developed to differentiate cinnamon (Cinnamomum) bark (CB) samples of the four major species (C. burmannii, C. verum, C. aromaticum, and C. loureiroi) of cinnamon. Fifty cinnamon samples collected from China, Vietnam, Indonesia, and Sri Lanka were studied using the developed FIMS fingerprinting method. The FIMS fingerprints of the cinnamon samples were analyzed using principal component analysis (PCA). The FIMS technique required only 1 min of analysis time per sample. The representative samples from each of the four major species of cinnamon were further examined using an ultrahigh-performance liquid chromatography-high-resolution mass spectrometry system, and the chemical differences between the four species were profiled. The results showed that the 1 min FIMS fingerprinting method successfully differentiated the four cinnamon species studied.