Abstract: Oplopanax elatus (Ci Ren Shen, in Chinese), a perennial bush with thorn, wildly grows in Chang Bai Mountain area, northeast China. The essential oil of its root, rhizome and stem was extracted by steam distillation with yields of 0.8～1.2%. By means of GC/MS/DS, 31 chemical constituents were identified as follows: n-hexanal (0.22%), heptaldehydc (0.17%), α-pinene (1.30%), β-pentyl furan(0.27%), n-octanal(2.07%), limonene(0.31%), ocimene(1.62%), δ-3-carene(0.19%), perillen(1.33%), 2,6-dimethyl heptalene(1.07%), borneol(1.27%), α-dodecenal(7.14%), α-copaene(0.54%), tetradcanal(1.17%), iaocaryophyllene (0.58%), β-farnesene(0.92%), α-caryophyllene(0.82%), γ-muurolene(0.73%), longifolene(1.67%), 3, 7, 11-trimethyl-2, 6, 10-dodinene(8.64%), γ-cadinene(2.79%), δ-cadinene(5.03%), nerolidol(14.93%), gualol(4.20%), torreyol(10.0%), cedrol(4.24%), bulnesol(7.79%) and farnesol(1.16%).The antimycotic activities of Ci Ren Shen cssential oil was determined in vitro by serial dilutions on solid nutrient medium. Fungistatic results were visible on 5 species, Microporum gypseum, M. lanosun, Trichophyton gypseum, T. purpureatum and Epidermophyton floccosum. The MIC is 0.0625%.