The common causes of lumbar pain after staying up late are the following: first, excessive strain on the lumbar muscles, stay up late working or studying, the lumbar muscles need to bear the weight of the body for a long time as well as stabilize the lumbar spine, unable to get rest and recovery, so the lumbar muscles continue to be tense, which can cause muscle stiffness, insufficient blood supply in the muscles leads to congestion and edema in the lumbar muscles, manifested as lumbar muscle pain symptoms. Secondly, the waist is cold, working or studying at night, the ambient temperature gradually decreases, the waist is easily attacked by cold leading to waist pain symptoms. In addition, the body’s thermoregulatory mechanism is in a state of inhibition at night, while not replenishing heat in time at night can also make the body unable to properly combat the low ambient temperature causing cold in the lumbar region. Treatment methods can be local heat compress and ultrashort wave therapy on the lumbar region, 1-2 times a day for 30 minutes each time, together with bed rest and axial turning to make the lumbar muscles get sufficient rest, which can relieve the symptoms of lumbar pain.