Spinal cord is the main pathway of communication between brain and peripheral nervous system. Spinal cord injury (SCI) often leads to sensory and motor functional deficits below the injury level, causing severe disability and bringing heavy burden to family and society. Spinal cord injury repair is one of the most challenging medical problems, and no effective therapeutic methods has been developed. The spinal cord is a complex tissue composed of various types of nerve cells, nerve fibers, and blood vessels. After SCI, the injury distance usually reaches several centimeters, resulting in the loss of multiple cells and the interruption of neural connections.