Abstract: Objective: To investigate the application value of spiral CT in psoas lesions.Methods: A retrospective analysis of spiral CT data of 110 cases of psoas lesions confirmed by surgical pathology or clinical.Results: Psoas hematoma in 37 cases(acute hematoma in 30 cases,chronic hematoma in 7 cases),the acute hematoma manifesting as psoas fascia thickening,enlargement volume,inhomogeneous high density,all with the transverse process fracture,follow-up CT showing the thin volume and the reduced density.In the chronic phase,the liquefied hematoma presenting watery density.The psoas involved by infection in 28 cases(tuberculosis in 21 cases,the other infections in 7 cases),CT showing the psoas muscle swelling,fuzzy contour,bands and effusion in the peritoneal fat clearance,follow-up CT could change due to the outcome of lesion,tuberculosis may be associated with the vertebral and accessories destruction;Psoas tumors in 45 cases,15 cases of them were direct invasion from abdominal malignant tumor,metastasis in 30 cases(the simple psoas metastasis in 3 cases,the spine metastasis simultaneously in 27 cases),CT showing an enlargement of the psoas and a significantly enhancement of the tumor.Conclusion: It is crucial significance for the diagnosis to understand the CT features of psoas lesions.