Abstract: The chemical constituents of essential oil from buried wood of Hainan Cypress were separated and identified by GC-MS. Relative contents of essential oil were determined by peak area normalization. 39 compounds from the essential oil were separated and identified, which account for 91.843 % of total essential oil. The main chemical constituents and contents were cedrol (23.516 %), phthalalic acid (11.843 %), D-limonene (10.103 %), dibutyl phthalate(9.843 %) and phenol(5.324 %). The test of the corrosion resistance showed that Hainan Cypress had strong inhibitory on growth on Gloeophyllum trabeum Murr and Coriolus versicolor.(4.365 % and 4.58 % of weight loss of wood sample were determined in the base and middle of Cypress Gloomy wood respectively)