Abstract: Recent literatures on antitumor effect, mechanism, and application of snake venom were summarized. This study aimed to provide a basis for the research, development, and application of snake venom which includes antitumor components. The abilities of snake venom was found in inhibiting tumor proliferation and migration and/or inducing apoptosis in a variety of malignant tumor cells at dose-dependent and/or time-dependent manner. Some types of snake venom inhibit tumoral angiogenesis. Meanwhile, the antitumor mechanisms of snake venom were as follows: 1) inhibit tumor metastasis by blocking certain signaling pathways, 2) induce apoptosis of tumor cells by activating the death pathway, 3) inhibit growth and proliferation of tumor cells by regulating the expression of tumor suppressor (promoter) genes or arresting the cell cycle, and 4) inhibit tumoral angiogenesis by inhibiting the expression of VEGF from cancer cells. Thus, snake venom has potential as an antitumor agent.