The three-step pain relief method for cancer is a method of pain relief based on the principle of using different levels of pain medication depending on the patient’s pain level. As one of the most common and effective pain relief methods, it is highly recommended by the World Health Organization (WHO) and has been widely used in the treatment of various types of chronic pain. The prerequisite for using the three-step pain relief method is to learn how to assess the cancer pain level. To classify a patient’s cancer pain into mild, moderate or severe, the most common method is to use the 0 to 10 pain evaluation scale. The doctor asks the patient to answer the question: “If 0 is no pain and 10 is the most pain you can imagine, then what is your current pain level? What is the worst pain level? What is the mildest pain level?” Grade 1 to 4 is mild pain, the patient has pain but can tolerate it and can live normally; grade 5 to 6 is moderate pain, the patient has obvious pain, cannot tolerate it and affects sleep; grade 7 to 10 is severe pain, the pain is severe, cannot sleep, and may be accompanied by passive posture or vegetative nerve dysfunction performance. After clarifying the patient’s pain level, then administer drugs according to the 5 main principles of cancer pain treatment proposed by WHO: I. Oral drug administration. It is convenient, non-invasive and easy for patients to take medication for a long time, which is applicable to most pain patients. Secondly, give the medication on time. Note that the medication is given “on time”, not only when the pain is present. Third, according to the three-step principle of drug administration. According to the different degrees of pain, different steps of medication are given to patients with mild, moderate and severe pain. Here we list the drugs commonly used in each ladder. The first step is to give non-opioid (non-steroidal anti-inflammatory drugs) plus or minus adjuvant analgesics for mild pain. Note: There is a maximum effective dose (ceiling effect injection) of non-steroidal analgesics. Commonly used drugs include paracetamol, aspirin, diclofenac, plus Hepatitis B, ibuprofen, fenpropathrin (ibuprofen extended-release capsules), anti-inflammatory pain, indomethacin, Isidin (indomethacin controlled-release tablets), etc. Weak opioids plus or minus NSAIDs and adjuvant analgesics are given for moderate pain in the second tier. Weak opioids also have a ceiling effect. Commonly used drugs include codeine, prednisolone, tramadol, chimantin (tramadol extended-release tablets), diclofenac (codeine controlled-release tablets), etc. Third order severe pain is given with opioids plus or minus NSAIDs and adjuvant analgesics. Strong opioids have no ceiling effect but can produce tolerance and require appropriate dose increases to overcome the tolerance phenomenon. In the past, morphine was thought to be addictive for pain relief, so patients were reluctant to use morphine. This view has now been proven wrong, and very few cancer pain patients who use morphine develop addiction. Commonly used drugs in this ladder include morphine tablets, Mefecam (morphine extended-release tablets), Methocarbamol (morphine controlled-release tablets, which can be administered rectally) and so on. However, dulcolax, a previously commonly used analgesic, is not recommended for the control of chronic pain due to factors such as the high toxicity of its metabolites. In addition, the use of some adjuvant drugs has increased the efficacy of pain relief, reduced the dose of analgesics, and provided good pain relief. These drugs include the corticosteroids dexamethasone and prednisone, which can reduce pain caused by peripheral nerve edema and compression; the antidepressants amitriptyline, doxepin, Mysore, and Prozac, which are used for analgesia, sedation, and mood improvement; the anticonvulsants carbamazepine and phenytoin sodium, which can treat tearing and burning pain and post-radiotherapy pain; and the hydroxyzine antihistamines, which are used for analgesia, sedation, and antiemesis. Fourth, the individualization of medication. The dose of medication should be determined according to the individual patient’s condition, and the purpose is to be painless, so that the dose should not be too strictly limited and lead to underdosing. V. Closely observe the changes of patients after medication, promptly deal with the side effects of various drugs, observe and evaluate the efficacy of drugs, and promptly adjust the dosage of drugs. In addition, attention should be paid to the interaction between drugs and the integrated treatment of drug pain relief combined with other methods. Recently, the State Drug Administration abolished the extreme limit of morphine use for cancer patients, which reflects the determination of government departments to promote the three-step treatment for cancer pain and the support of our government for cancer pain control and palliative care. For medical personnel, it is imperative to change old concepts and learn the necessary knowledge of pain medication.