The spastic cerebral palsy of both lower limbs is common in preterm infants. Due to the immaturity of the brain in charge of motor development that is born, the brain cells are damaged and cannot inhibit muscle contraction, resulting in continuous excitation and contraction of the lower limb muscles, which manifests as stiffness of the lower limbs, great resistance to flexion and extension of the lower limb joints, or spasticity in medical terminology, and increased muscle tone. The child has a stiff gait, scissor gait, pointed feet, and walks with great effort. Over time, muscle tendon contractures, lower limb deformities, and unbalanced force lines can occur, seriously affecting the child’s ability to walk. Therefore, how to relieve lower limb spasticity becomes an important issue in the treatment of cerebral palsy. Conservative treatment methods include massage, acupuncture, electrotherapy, botulinum toxin injection, etc., which have certain effect and are prone to relapse. Generally, the effect of botulinum toxin can be maintained for 3-6 months. Selective posterior spinal nerve rhizotomy (SPR) is the most effective way to relieve spasticity. It relieves spasticity by blocking excessive excitation transmission from the lower nerve centers, with the advantages of complete relief of spasticity, significant reduction of muscle tone, preservation of sensory function, and significant improvement of walking ability. The key to the effectiveness of SPR treatment is the word “highly selective”. Specifically: 1) the type of cerebral palsy is selected as spastic; 2) the muscle tone is selected as grade 3 or above; 3) the muscle strength is selected as 3+ or above, i.e. children with walking ability; 4) the nerves are cut, the posterior root is cut, the anterior root is preserved, the lumbar 2nd, 3rd, 5th and sacral 1 are cut, and the lumbar 4th nerve is preserved; the cut ratio is selected as about 30% for lumbar 2nd and 3rd, and about 50% for lumbar 5th and sacral 1, which is also adjusted according to the muscle tone size. 5, each nerve within the selection of which part of the cut, through the nerve stimulator to select the excitability of high nerve fibers cut. As can be seen, this is a relatively complex surgery, requiring doctors with extensive clinical experience, to be able to make accurate preoperative assessment, precise surgical operation, in order to take effect.