Abstract: Elemene is a terpene compound extracted from the traditional Chinese herbal medicine Curcuma wenyujin. Elemene injection, whose main ingredients are β-, γ-, δ-elemene mixtures, was an anti-tumor phytochemical drug developed independently in China and was approved and successfully marketed as an anti-tumor new drug of category 2 in 1995. The extensive application of elemene over the past 20 years has accumulated much valuable experience in the study of its anti-tumor activity. There has been more and more medical evidence in elemene injection, with research results showing its broad antitumor spectrum, definite clinical efficacy and few side-effects. Furthermore, elemene injection has been found to be different from other traditional cytotoxic chemotherapeutic drugs. Besides its direct anti-tumor effect, elemene injection could also reverse drug resistance of tumor cells, inhibit metastasis and improve immunity, and decrease toxicity and increase efficacy when combined with radiotherapy and chemotherapy. The advances in research on anti-tumor mechanisms of elemene injection have been reviewed in this paper.