Pain is a common clinical manifestation for patients with advanced cancer. Pain in advanced stage is usually moderate and severe pain, which seriously affects sleep and can also be accompanied by disorders of plant nerve function, because pain is in passive position, sleep is basically impossible, normal life is impossible and psychological burden will be increased. Pain can also directly or indirectly inhibit the immune function of the body, thus accelerating the growth and metastasis of tumor. Therefore, pain in patients with advanced cancer can cause serious adverse effects on the nervous system, circulatory system and respiratory system of the organism, and eventually form a vicious circle of pain. At present, in addition to anti-tumor treatment, analgesic drugs can also be given to relieve the symptoms of pain in advanced cancer.