The numbness of one leg with pain may be caused by the following reasons: 1, lumbar disc herniation, when the marginal lumbar disc herniation compresses the nerve root on one side, there will be numbness and pain on one leg, accompanied by weakness of the toes. 2, lumbar spinal stenosis, lumbar spinal stenosis serious compression of the nerve and lead to numbness and pain on one leg, which can be accompanied by pain on one hip, often accompanied by limp walking. 3, lumbar spine slippage, serious lumbar spine slippage can also compress the nerve root and lead to numbness of one leg, then CT, X-ray and nuclear magnetic examination should be conducted to further confirm the diagnosis and treatment. 4, nerve root lesions, when the nerve root tumor will also appear nerve root compression, leading to leg numbness, pain symptoms. 5, pear-shaped muscle syndrome, can appear on one side of the sciatic nerve compression, leading to leg pain, leg numbness. This can lead to leg pain and numbness.