Low back pain with thigh pain may be caused by the following reasons: first, lumbar disc herniation, when the lumbar disc herniation compresses the nerve roots, it can be accompanied by thigh pain at the same time as low back pain, then the CT, MRI and X-ray examination of the lumbar spine for early diagnosis and treatment, mostly due to the 2-3 lumbar spine or 3-4 lumbar spine disc herniation compresses the nerve roots, and causes thigh pain; second, lumbar spinal stenosis, when the lumbar spinal stenosis herniated disc, hyperplastic bone spur or hypertrophic ligament can also compress the nerve roots and cause thigh pain. Second, lumbar spinal stenosis, when the lumbar spinal stenosis protruding discs, hyperplastic bone spurs or hypertrophic ligaments, can also compress the nerve roots and lead to thigh pain, then also need to carry out lumbar spine nuclear magnetic, CT examination for early diagnosis and treatment. If the condition is serious, surgery may also be required; third, lumbar spine slippage, lumbar spine slippage can cause lumbar pain and thigh pain by compressing the nerve when it is serious, then X-ray and MRI of lumbar spine should be performed for diagnosis; fourth, lumbar spine tumor or tuberculosis, patients with lumbar spine tumor or tuberculosis can have thigh pain and paraplegia in serious cases, then MRI of lumbar spine and blood tests should be performed for diagnosis and treatment. In this case, lumbar spine MRI and blood tests should be performed for diagnosis and treatment.