Taxol, a diterpenoid first isolated from Taxus brevifolia in 1971, invokes a great deal of interest amongst anticancer drugs from plant source due to its promising anticancer activity and unique action mechanism. Extensive chemical and biological investigations on this and related diterpenoids have been carried out worldwide for the purpose of ample and efficient material supply. Search for new taxoids from different kinds of Taxus species might not only lead to a solution of the problem but to a refinement of anticancer activity and formulation. As a part of our program to investigate new axanes of antitumor activity, we have isolated fourteen new diterpenoids from Chinese Taxaceae, Taxus chinensis, together with thirteen known compounds. Their structures were elucidated by spectral means, especially NMR technique. Among fourteen new diterpenoids, ten compounds possess a novel tricyclo 5/7/6-membered ring system, which was unambiguously confirmed by an X-ray analysis. The variable temperature NMR experiments indicated that some of new diterpenoids of this skeleton are more flexible in solution than their taxane counterpart, and exist as a mixture of two conformers at an ambient temperature.