Numbness of legs is considered to be caused by lumbar intervertebral disc herniation, spinal cord tumor, diabetes and other diseases. 1. Lumbar disc herniation: when the nucleus pulposus of the lumbar disc breaks through the posterior longitudinal ligament and compresses the nerve root, there may be radiating pain in one or both lower limbs, which may be accompanied by numbness, heaviness and weakness of the lower limbs, swelling and other sensory and motor abnormalities. 2. Spinal cord tumor: no matter benign or malignant tumor of spinal cord, it can cause spinal cord occupation, compression and stimulation of spinal cord causing sensory and motor abnormalities of limbs, such as numbness, pain, swelling, pins and needles sensation, feeling of stepping on cotton, and weakness of feet. 3. Diabetes mellitus: diabetes mellitus can cause peripheral neuropathy, peripheral nerve sensory and motor abnormalities, numbness of the hands and feet gloves and socks, can also be accompanied by retinopathy, foot necrosis and other symptoms. Numbness of the legs may also be caused by cerebral hemorrhage, spondylitis and other diseases, it is recommended to consult a doctor to clarify the diagnosis, under the guidance of the doctor for targeted treatment.