About 80% of patients with advanced cancer suffer from severe cancer pain, which can lead to a series of side effects such as accelerated heart rate, increased blood pressure and blood sugar, and significantly reduced body immunity, making the patient’s body collapse more quickly. At present, the treatment of cancer pain mostly adopts an integrated approach, with the “three-step program” recommended by the World Health Organization as the first choice, and the principles of implementing the “three-step program” are: 1. oral administration; 2. timely administration; 3. stepwise administration; 4. individualized drug dosage. The principles of the “three-step protocol” are: 1) oral administration; 2) timely administration; 3) stepwise administration; 4) individualized drug dosage. Intrathecal target-controlled infusion system placement is undoubtedly a good method to control advanced cancer pain. The basic principle of intrathecal target-controlled infusion system placement: morphine produces analgesia by acting on opioid receptors, which mainly exist in the brain and spinal cord. After oral administration, the drug is absorbed from the gastrointestinal tract, but before entering the whole body, part of it has been metabolized by the liver, and morphine can easily be combined with the liver and become ineffective; to enter the brain and spinal cord from the blood, the drug must pass a barrier called the blood-brain barrier, and only those fat-soluble drugs can easily enter and leave the brain and blood freely, while morphine salts are water-soluble drugs, so it is difficult to reach the brain and spinal cord through the blood-brain barrier. Intrathecal target-controlled infusion system placement is to inject morphine directly into the cerebrospinal fluid, while the brain and spinal cord are immersed in the cerebrospinal fluid, and the morphine in the cerebrospinal fluid is not easily cleared by metabolism. Therefore, some studies have shown that the morphine pump dose is only 1/300 of the oral dose to achieve the same therapeutic effect. This method can be used to treat cancer pain in almost all parts of the body. It is so effective that some people call it one of the ultimate cancer pain treatment methods. While treating pain, morphine pump does not affect patients’ daily life, and patients can shower, swim, and travel. The disadvantage is that it is more expensive.