The left side of the back pain in the morning can be caused by the following reasons: first, lumbar muscle strain, lumbar muscle strain patients can have the symptoms of lumbar muscle pain aggravated in the morning when they wake up, and can also aggravate when they are cold and tired, and can improve after a while of activity, then we should check the lumbar spine X-ray, CT, to exclude other diseases to diagnose. Secondly, lumbar dorsal myofasciitis, patients with lumbar dorsal myofasciitis can also have pain on one side of the lumbar back, and the pain is obvious when waking up in the morning, so it should be diagnosed by early physical examination and early physiotherapy and oral medication. Third, kidney deficiency, kidney deficiency can also have pain on one side of the waist in the morning, then we should go to the Chinese medicine department to take a pulse to diagnose, and early treatment of kidney medicine. Fourth, sacroiliac joint diseases, when the sacroiliac joint is involved for various reasons, there can be pain in the lower back and sacroiliac joint in the morning, then we should check the x-ray of sacroiliac joint and lumbar spine as well as blood test for diagnosis and treatment.