Oridonin is a deterpenoid isolated from Rabdosia rubescences. It has excellent antitumor effect, whose mechanism is to induce apoptosis of tumor cells by mitochondrial pathway. Signal transduction pathway play an important part in cell proliferation,differentiation,apoptosis and so on. Recent studies suggested that Oridonin may trigger mitochondrial apoptosis pathway by four signal transduction pathways,which were p53, Ras/Raf/ERK, PI3K/Akt and NF-κB pathway. Further investigation on mitochondrial signal transduction pathway would be helpful to clarify the intracellular target and the antitumor molecular mechanism of ORI.