The pain at the back of the thigh can be caused by the following reasons: first, the hip joint impingement syndrome, when the hip joint impact with the sciatic bone, there can be pain at the back of the thigh, which can be radiated to the inner and front side of the thigh, then it is necessary to check the body early and take early MRI and X-ray examination of the hip joint for diagnosis and early treatment. Secondly, when there is bursitis or tumor in the sciatic nodes, there can be pain at the back of the thigh, and there is often obvious percussion pain and pressure pain during physical examination, so early examination of the ultrasound, CT and MRI of the sciatic nodes is needed for early diagnosis and early treatment.