Patients with leg pain at night, but not during the day, the following common causes: First, leg muscle strain: work too hard during the day, at night rest within the leg muscle lactic acid accumulation too much, stimulating nerve endings and cause leg pain. After the night rest acidic metabolites out of the body, no obvious clinical symptoms of pain in the legs during the day. Second, severe osteoporosis or hypocalcemia: can lead to cramp-like pain in the legs at night, while the pain symptoms will disappear completely after daytime activities. Thirdly, excessive alcohol consumption: it causes excessive accumulation of acetic acid in the body, which stimulates the leg muscles and causes painful symptoms at night, while after metabolism, the alcohol will be significantly reduced during the day, so there is no obvious clinical symptom of pain during the day. Patients with the above symptoms should be diagnosed early and treated early to avoid prolonged symptoms.