The invention provides a beta-elemene halide, a preparation method therefor and an application of the beta-elemene halide. Specifically, the invention provides a preparation method for a compound witha structure represented by a formula I shown in the description, wherein each group is as defined in the description. The invention further provides a compound with a structure represented by a formula II shown in the description (each group is as defined in the description), a pharmaceutical composition containing the compound represented by the formula II, the compounds and isotope derivatives,chiral isomers, allosteric isomers, different salts, prodrug, preparations and the like of these compounds. The compounds can serve as intermediates and be used for preparing derivatives of elemene and treating various diseases capable of being treated by the elemene, including lung cancer, mammary cancer, liver cancer, and the like.