Low back pain is a common clinical disease seriously affects the quality of people's lives. And this disease takes up a large proportion in the crowd. Incipient lumbago is hard to diagnose and often hidden morbidity. If early symptoms are ignored by patients, it will greatly influence the quality of life in the future. This study will use 3.0T MRI to distinguish the difference of lumbar small joints, intervertebral discs, ligaments and muscle between the normal and the pain.