Ginsenosides, belonging to a group of saponins with triterpenoid dammarane skeleton, show a variety of pharmacological effects. Among them, some ginsenoside derivatives, which can be produced by acidic and alkaline hydrolysis, biotransformation and steamed process from the major ginsenosides in ginseng plant, perform stronger activities than the major primeval ginsenosides on inhibiting growth or metastasis of tumor, inducing apoptosis and differentiation of tumor and reversing multidrug resistance of tumor. Therefore ginsenoside derivatives are promising as antitumor active compounds and drugs. In this review, the derivatization methods, ginsenoside derivatives and their anti-tumor structure-activity relationship have been summarized for providing useful information for the research and development of novel antitumor drugs.