Objective To evaluate the imaging features of spherical pneumonia(SP)and to differentiate it from other spherical lesions,particularly from pulmonary carcinoma.Method 32 cases of SP clinically proved were analyzed retrospectively.Results The main CT findings were as follows:(1) Bilateral margins of the lesions were perpendicular to pleura with a straight cut-edge presenting a square sign.(2) The following manifestations strongly meaned SP:adjacent pleural thickness;symmetrical bronchial wall thickness without bronchial stenosis;hilar blood vessel proliferation,enlargement and kink but not rigidity;small patches of slight high density around lesions apart from pleura.(3)Shrink of lesions after anti-inflammatory therapy inclined to SP.(4) There were not mediastinal and hilar lymph enlargememt.(5) "halosign","bronchiologram" and "vacuole"were not special to SP.Conclusion CT examination is a effective way of diagnosis and differentiation to SP.