Adolescents often back pain can be caused by the following causes: first, the lumbar spine and sacral spine occult cleft, which is a congenital developmental deformity of the lumbar spine and sacral spine, can be accompanied by frequent back pain, especially after sedentary back pain is very obvious, this time to take early X-ray and CT of the lumbosacral spine to diagnose and treat. Second, lumbar spine slippage, lumbar spine slippage is often due to congenital lumbar spine isthmus cleft, lumbar spine slippage patients can have symptoms of lumbar pain, the patient can not bend and can not sit for a long time, then we should check the lumbar spine x-ray to diagnose and treat. Third, lumbar disc protrusion, lumbar disc protrusion can be seen in part of the patients in adolescents, can have low back pain, accompanied by symptoms of lower limb discomfort, then we should check the CT, MRI of the lumbar disc to diagnose and treat. Fourth, tumor of lumbar spine, which is an uncommon cause, can lead to low back pain, accompanied by systemic symptoms, such as wasting or loss of appetite, then the MRI of lumbar spine should be examined to diagnose and treat.