In order to improve the quality of life of cancer patients, WHO established the Expert Committee on Cancer Pain Treatment in 1982, formulated the principle of three-step analgesia, and proposed the goal of “making cancer patients pain-free worldwide by the year 2000”. The Ministry of Health of China responded positively to this call and took a series of measures, such as setting up a professional association for cancer rehabilitation and palliative care in China, holding national workshops and seminars, issuing guiding documents and study materials, and adjusting the supply policy of narcotic drugs. As a result, pain treatment in China has made great progress compared with the starting stage, but there is still a huge gap with the needs and requirements. According to the WHO three-step principle, more than 80% of patients can obtain adequate pain relief through opioid, non-opioid analgesics and adjuvant drug therapy, while the situation of cancer pain in China is still very serious. In China, there are about 2 million new cancer patients each year, and the incidence of pain is about 40%-65%, among which 15%-30% are in early stage, 40%-50% in middle stage, and 50%-70% in late stage. Up to 60% of these cancer pain patients still have pain, and the proportion is as high as 70% in late stage.