Soft corals of the genus Briareum (Briareidae) have been well known as a rich source for marine natural products with novel structural features. Briarane-related natural products attracted the attentions of researchers because of the structural complexity and interesting biological activity associated with numerous compounds of this type. Previous studies on the secondary metabolites of wild-type and cultured Formosan octocoral Briareum excavatum were collected around the sea area of Kenting. In the thesis of our studies on secondary metabolites from marine organisms, the acetone-soluble of the Formosan octocoral B. excavatum collected at Orchid Island has led to the isolation of eleven briarane-type diterpenoids (1−11), compounds 3, 4, and 6−10 are new compounds. The structures of these compounds were determined on the basis of their spectroscopic analysis (1H NMR, 13C NMR, 1H−1H COSY, HSQC, HMBC, NOESY, IR and mass spectra) and physical data by comparison of the physical and spectral data with those of the related literatures. The antiviral activity against HCMV (human cytomegalovirus) cells of these secondary metabolites was evaluated. Metabolite 8 exhibited significant activity against HCMV cells and compound 11 showed anti-inflammatory activity.−