Although the WHO proposed the three-step oral drug treatment for cancer pain as early as 2000, hoping to achieve a pain-free life for patients with advanced cancer. Due to the fear of opioid addiction and the strict control of such drugs, or the inability to take oral medication, or the side effects of oral medication are too great, in fact, more than 60% of advanced cancer pain patients are still suffering from pain. In addition to the standardized implementation of WHO’s three-step treatment, pain departments of major hospitals have also carried out a variety of minimally invasive interventions to open up the fourth step for cancer pain treatment, among which the intratarget infusion system “intrathecal morphine pump” has become the ultimate treatment for advanced cancer pain because of its precise analgesic effect and its applicability to all kinds of advanced cancer pain. The working principle of intrathecal morphine pump is to put a very thin silicone catheter into the subarachnoid space (intrathecal) of the patient’s lumbar region through a puncture needle, and the other end of the catheter is buried under the patient’s skin, and an electronic pump containing morphine is connected to the subcutaneous end of the catheter. The morphine in the pump can be injected directly into the subarachnoid space, which is connected to the brain. Compared with subarachnoid administration in the spinal cord, the effective dose of oral drugs or intravenous drugs that can really enter the brain for analgesia is very small, and most of the drugs also need to be metabolized by the liver and kidneys, which increases the burden on the liver and kidneys and produces many side effects. The advantages of morphine pump 1.Morphine pump can deliver the drug directly to the subarachnoid space of the spinal cord, which is connected with the brain, to play a direct analgesic effect; 2.The dose of the drug administered by morphine pump is only one third of the oral dose and one percent of the intravenous dose; 3.It can greatly reduce the burden of liver and kidney and the incidence of various side effects. Because it acts on pain in all parts of the body through the brain, it can play an effective analgesic effect on all kinds of advanced cancer pain, thus becoming the ultimate treatment for advanced cancer pain.