According to the World Health Organization, about 30%-50% of cancer patients have varying degrees of pain, and the incidence of moderate to severe pain in advanced cancer patients can increase to 75%. The World Health Organization suggests that cancer pain should be taken seriously, and cancer pain can be treated, and 80% of patients can get pain relief through a relatively simple method, i.e. three-step pain relief therapy. The basic principles of analgesic drug therapy 1. The so-called three-step approach to cancer pain treatment is to select the appropriate analgesic according to the patient’s pain level and cause after a proper assessment of the nature and cause of cancer pain. In other words, patients with mild pain should mainly use analgesics of antipyretic analgesic class; for moderate pain, weak opioids should be selected; for severe pain, strong opioids should be selected. Choose non-opioid analgesics ± adjuvant drugs for mild pain; choose weak opioids ± non-opioid analgesics ± adjuvant drugs for moderate pain; strong opioids ± non-opioid analgesics ± adjuvant drugs for severe pain. 2.Orally administered drugs: or non-invasive drugs (such as transdermal patches) or less invasive routes of administration to facilitate long-term use of drugs, especially for long-term use of strong opioid analgesics. 3. Timely administration: Cancer pain is usually chronic and persistent, therefore, pain medication should be administered regularly “on time”, rather than “on demand” when the pain is severe. 4.Individualized dosing: The dose of opioid drugs varies greatly among individuals. Individualized dose titration of opioid analgesics is the focus and difficulty of clinical work in pain treatment. The basic principle of dose titration is to titrate the dose of analgesics (including the dose administered on time and when necessary) to the ideal level of pain relief and low side effects.