In fusion of lumbar spine, every fused motion segments shows varisble limitation of motion in flexion, extension and lateral bending according to their types and level of fusion. The motion segment of lumbar spine is three joint complex which consists of posterior two articular facet joints and an anterior intervertebral disc. Nowadays, orthopedic surgeon prefer anterior fusion due to direct identification and removal of diseased tissue, reduction of fractured fragments, restoration of intrevertebral space, early rehabilitation and no damage of nerve root and cord, and is prefered short Segmental Spinal Instrumentation(e.g. Cotrel Dubousset Instrumentation, etc.) due to short and rigid fusion, no necessity of external support and low limitation of motion. We studied 58 cases of fused lumbar spine which had been operated since Sep.1983, by X-ray overlay method and 20 cases of healthy lumbar spine as eontrol group. In this study, we obtained following results ; 1. Harrington Rod Instrumentation reveals the most remarkable limitation of motion, whereas, C.D.I. and A.I.F. reveal the least limitation of motion. 2. Distinct differencies of motion are repersented by its range of fusion and range of motion in 2 segmental fusion reveals remarkable decreasement from range of motion in single segmental fusion. 3. In single segmental fusion, the most limitation of motion was represented in Harrington Rod Instrumentation and posterior fusion with bone graft. There is remarkable decreasement of flexion at lumbosacral junction by its site of fusion. 4.In double segmental fusion, the most limitation of motion was represented in Harrington Rod Instrumentation and there is no significant difference of motion by its site of fusion.