Object To study the chemical constituents from the fruits of Juniperus formosana Hayata. Methods The compounds were isolated and purified on liquid-liquid, silica gel, and aluminium oxide column chromatography, their structures were identified by spectroscopic methods, such as GC-MS, 1H-NMR, and 13C-NMR, especially 2D-NMR. Results Two new oxygenated diterpenoids, named labdatriene (Ⅰ) and labdadiene (Ⅱ), were isolated from the ethyl acetate extract. Their structures were determined to be 19-carboxy-8(17)-13(16)-14-labdatriene and 15, 19-dihydroxyl-8(17)-13(E)-labdadiene, respectively. Conclusion Compounds Ⅰ and Ⅱ are new diterpenoids.