The causes of chronic low back pain are complex and include skeletal and muscular system diseases and other organ diseases. The common causes are as follows: 1. Mechanical (structural): such as muscle ligament injury, disc herniation, degenerative degeneration of vertebral joints, spinal stenosis, spinal deformity, vertebral slippage, hypertrophic osteoarthritis, fracture and nerve root sheath fibrosis. 2, inflammatory: (serum reactive arthropathy) such as ankylosing spondylitis, psoriatic arthritis and rheumatoid arthritis. 3, Infection: (sepsis, tuberculosis, fungal infection and viral infection) sacroiliac arthritis, vertebral osteomyelitis, vertebral tuberculosis, and lumbar major muscle abscess. 4, tumor: primary and metastatic tumors. 5, metabolic: osteoporosis, cartilage calcification, deformational osteitis, etc.