Two new diterpenoids, konishone (1) and 3b-hydroxy-5,6-dehydrosugiol (2), along with three known diterpenoids--hinokiol (3), sugiol (4), and 12-hydroxy-6,7-secoabieta-8,11,13-triene-6,7-dial (5)--were isolated from the wood of Cunninghamia konishii. Compound 1 is a novel skeleton of the 7,20-dinorabietane-type diterpene. In addition, when RAW264.7 macrophages were treated with different concentrations of compounds 1, 3, and 5 together with LPS, a significant concentration-dependent inhibition of NO production was detected. The IC₅₀ values for inhibition of nitrite production of compounds 1, 3, and 5 were about 9.8 ± 0.7, 7.9 ± 0.9, and 9.3 ± 1.3 μg/mL, respectively. This study presents the potential utilization of compounds 1, 3, and 5, as lead compounds for the development of anti-inflammatory drugs.