Abstract: The anticancer drug taxol is a new type antimicrotubular drug. The structure-activity relationship study on taxol and its analogs has indicated the importance of the C₁₃ side chain and the C₄-C₅-C₂₀ epoxypropane group. The crystal structures of 4 taxoids having the basic skeleton with 5/7/6 membered ring and three types of 10 taxoids having the basic skeleton with 6/8/6 membered ring have been analyzed. The effects of the induction by different substructures at C₄ on the stereostructures of taxoids were studied, and the relationship between the 6/8/6/4 skeleton and the anticancer activity was discussed from the crystallographic point.