In the standing lateral position, the pelvis is tilted in some degree anteroinferiorly. But there was no accurate and standard measurement about the pelvis tilting. The pelvis tilting affects on the lumbar lordosis, weight bearing area of the hip joint, and the anteversion of acetabulum. In the standing true lateral view of the pelvis, 5 points were marked: midpoint of both anterosuperior iliac spines (M), upper margin of symphysis pubis (S), lower margin of symphysis pubis(S), sacral promontorium (SP), coccyx tip (C). And using the additional horizontal plane (H), we measured the 4 angles : angle I ( < MSH), angle II ( < SPSH), angle III(