The causes of thigh root pain when lifting the leg are mainly related to hip joint lesions, such as femoral head necrosis, osteoarthritis of the hip joint, greater trochanteric bursitis, or lumbar spine diseases, such as lumbar intervertebral disc herniation, etc.; if it is transient, it may also be a physiological phenomenon after exertion. 1. Hip diseases: such as femoral head necrosis, osteoarthritis of the hip joint, acetabular impingement syndrome, hip dysplasia, etc., which can be clearly diagnosed by X-ray film and MRI examination. 2. Bursitis of the greater trochanter: generally in the thigh root lateral pressure pain of the greater trochanter is more obvious, mostly caused by repeated local friction and excessive tension of tendons. 3. Lumbar spine diseases: such as lumbar disc herniation, lumbar spondylolisthesis, etc.: caused by the compression of the corresponding nerve roots, usually accompanied by lumbar pain and discomfort. 4. Physiological phenomenon: after overexertion and a lot of exercise, there is a transient thigh pain, which may be a physiological phenomenon caused by the accumulation of lactic acid. If the pain is not relieved or continues to worsen, it is necessary to go to the hospital in time to clarify the cause of the disease and follow the doctor’s instructions for treatment.