The invention provides a cancer pain plaster composed of nux vomica, Hindu datura flower, pendulous monkshood root, dried Chinese toad skin, paniculate swallowwort root or herb, yanhusuo tuber, panax notoginseng, and an auxiliary material of borneol. One plaster comprises, preferably, 1.0g of nux vomica, 1.0g of Hindu datura flower, 1.0g of pendulous monkshood root, 1.0g of dried Chinese toad skin, 1.0g of paniculate swallowwort root or herb, 2.0g of yanhusuo tuber, 1.0g of panax notoginseng, and the auxiliary material of borneol. According to the technology, authentic pure traditional Chinese medicines are selected, and scientific formulation and rigorous production process are adopted. The materials are refined, and effect is concentrated. An effect can be provided after 20min of application, and a pain-relieving effect can last for 24h. Therefore, a substantial pain-relieving effect can be provided for continuous cancer pain. Especially, the plaster has relieving and stopping effects against long-term severe pains. When the plaster is repeatedly applied, no toxic or side effect is provided, and addiction is prevented. The plaster causes no irritation or allergy to skins, and is suitable to be used against various pains caused by various cancer primary tumors and metastases. With the plaster, patient pain can be relieved, symptoms can be relieved, and substantial pain relieving effects and concentrated pain relieving functions such as blood circulation activating, stasis removing, collateral dredging, qi regulating, and stagnation eliminating are provided.