Objective To probe into diagnostic value of CT and X-ray plain film for osteoarthritis of lumbar vertebrae.Methods We analyzed signs on CT images and X-ray plain film images of 108 osteoarthritis of lumbar vertebrae.Results X-ray plain film was superior to CT in showing signs of hyperostosis,degeneration of intervertebral small joints and intervertebral space narrowing.CT was superior to X-ray plain film in showing Schmorl's nodes.Intervertebral space narrowing was interrelated with disc protrusion.Conclusion Osteoarthritis of lumbar vertebrae can be diagnosed by CT scanning and X-ray plain film.Some signs of degeneration can be shown by CT,but X-ray plain film can't.It is necessary to make CT scanning when we want to know pathological changes of disc and nerve.