Female patients with left posterior lumbar pain, in the clinic is common in the following three categories of diseases: 1, because of long-term stooping activities caused by lumbar muscle strain or lumbar disc herniation, usually need to further lumbar spine CT examination, the treatment is mainly used to rest, lying down. 2, mainly in the urinary system diseases, including urinary stones or urinary tract infections, such as pyelonephritis, usually need to further urinary ultrasound examination or urine routine examination, and if necessary, also need to perform urine culture. 3, mainly in the urinary system diseases, including urinary stone or infection, such as pyelonephritis. Ultrasound examination of the urinary system or urine routine examination, if necessary, also need to perform urine culture. If it is a urinary tract infection, a sensitive antibiotic is usually needed. If it is a urinary stone, usually the use of drugs, larger stones need to be crushed, if necessary, surgical removal of stones. 3, mainly female pelvic inflammatory disease, secondary caused by the left lumbar pain and discomfort, usually need to be further pelvic ultrasound examination to clarify the diagnosis. Treatment, mainly using anti-inflammatory and other conservative treatment, and even need surgery if necessary.