-A new sesquiterpenoid, 11-hydroxy-valenc-1(10),3(4)-dien-2-one (3), two chemically synthesized but first isolate from nature, 3-oxocedran-8β-ol (1) and valenc-1(10),3(4),11(12)-trien-2-one (2) along with four known compounds, sugiol (4), (+)-nootkatone (5), 11-hydroxy-valenc-1(10)-en-2-one (6), and clovandiol (7), were isolated from the heartwood of Juniperus chinensis. All chemical structures were elucidated using extensive spectroscopic analysis including 1D and 2D NMR spectroscopy. Valenc-1(10),3(4),11(12)-trien-2-one (2) exhibited significant inhibitory activity against butyrylcholinesterase with an IC 50 value of 68.45 µM.