In order to clarify the main pathogens during the preservation of tomato, rDNA-ITS protocol was applied to identify eight pathogens with different morphology isolated from Solanum lycopersicum var. cerasiforme fruits. The bacteriostatic effect of cinnamon essential oil on these post-harvest pathogens was studied by using direct contact in vitro and inhibition zone. The results were as followed: The eight pathogens could be divided into five categories: Cladosporium, Penicillium, Alternaria, Botrytis and Trichothecium. Cinnamon essential oil had a moderate bacteriostatic effect on these five clusters of pathogens. The inhibitory performances from strong to weak were Trichothecium roseum, Alternaria brassicae, Penicillium expansum, Cladosporium cladosporioides, Botrytis cinerea. In the experiment of sensitivity performances, the most sensitive pathogen was T. roseum, and the least sensitive one was C. cladosporioides. Using GC-MS analysis for cinnamon essential oil composition, 75% of the ingredients had antibacterial effect. The study of bacteriostatic experiment showed that cinnamon essential oil had promisingly bacteriostatic effect and could be used as a natural preservative for tomato after harvesting.