The reason why rehabilitation medicine emphasizes early rehabilitation of stroke patients is based on the theory of brain plasticity and functional reorganization. In the past, it was thought that the nervous system could not be regenerated after a neurological injury. Therefore, many stroke patients lived with physical dysfunction for the rest of their lives. Later, medical doctors put forward the theory of brain plasticity. That is, after a brain injury, the body has the ability to repair itself, just as any part of the body will repair and heal itself after a breakage. Brain tissue also performs some of the patient’s functions through intra- and inter-system functional reorganization such as regeneration of axons and long shoots of side branches, and re-activation of previously unused tissue. With rehabilitation, although many patients do not return to their original level of function, 95% of patients can regain the ability to walk and 30% can return to light work. The prerequisite to achieve functional reorganization is to do purposeful and selective training. The period from day 3 to day 30 after brain injury is the period when rehabilitation training is most effective. In addition to the rehabilitation of hemiplegic patients with stroke, early rehabilitation is also emphasized for paraplegic patients. For many patients with spinal fractures and spinal cord injuries, rehabilitation cannot be started until the fractures have healed. If rehabilitation is started only after the fractures have healed, many complications such as osteoporosis, urinary tract infection, deep vein thrombosis, joint contracture, etc. will occur, and the recovery of the nervous system will be affected. Special emphasis is placed on the fact that some patients with spinal cord injury are not completely injured, so if we can take the time to rehabilitate early, we can not only promote the recovery of function, but also achieve twice the result with half the effort. For patients with spinal cord injuries, even if the fracture does not heal, the rehabilitation physician will adopt many feasible treatments to promote both neurological recovery and fracture healing, which will also reduce many complications. Some patients with benign spinal tumors have limb immobility before surgery, or limb immobility after surgery. The rehabilitation surgeon also has to analyze whether the patient has a complete injury or an incomplete injury. If it is an incomplete injury, it is very important to provide reasonable and timely rehabilitation training at an early stage. We recently admitted a post-operative patient with a thoracic spinal chordoma who not only had no sensation present in both lower extremities at the time of intake, but was unable to move at all. Ten days after the patient’s surgery, we started rehabilitation training, and after more than two months of treatment and scientific training, the patient is now able to move his legs on his own. Early rehabilitation should also be emphasized for patients with complete injuries. This is because it is within the area of complete injury that the zone of partial preservation of function (ZPP) can exist. It is also believed that the reason for some recovery of the lower extremities after spinal cord injury is due to the action of the central-type generator structures present in the lumbar spinal cord. The role of rehabilitation is important in both brain and spinal cord injuries. It is important to emphasize not only early rehabilitation, but also persistent rehabilitation. The role of rehabilitation is amazing. A professor of rehabilitation medicine in the United States had a father who had a brain stem infarction at the age of 66. After rehabilitating to gain the ability to walk and care for himself, he then took up mountaineering and died of a myocardial infarction at the age of 77 while climbing to 9,000 feet. The professor of rehabilitation medicine then performed an autopsy on his father and was surprised to find that only 3% of his father’s conus fasciculus was intact, while 97% of that portion had pathological changes. This shows how strong the compensatory capacity of human beings is, and the performance of this compensatory capacity depends on rehabilitation training, especially early and scientific training.