The present invention belongs to the field of natural medicine and pharmaceutical chemistry, and specifically relates to novel 2-alkyl- or 2-aromatic-substituted tanshinone I derivatives of formula (I) or a pharmaceutically acceptable salt thereof, to a process for the preparation of these compounds, compositions containing such compounds and their use in preparing antineoplastic medicaments. When Z=R, said derivative is 2-alkyl-substituted tanshinone I； when Z=Ar, said derivative is 2-aryl-substituted tanshinone I； when Z=Het, said derivative is 2-heteroaryl- or 2-heterocyclyl-substituted tanshinone I.
