Abstract: Objective To analyse CT image features of primary pulmonary cryptococcosis (PPC) in immu-nocompetent or immunosuppressive patients in order to improve its cognitive and diagnostic level.Methods We analyzed retrospectively 43 cases with primary pulmonary cryptococcosis (PPC) from our hospital during February 2008 to February 2015. All the cases were confirmed diagnosis by pathology through surgery or CT-guided percutaneous lung biopsy. CT manifestations of the two groups (immunocompetence and immunosuppression) were analyzed.Results Imaging characteristics on CT were divided into 5 types: (1) solitary nodule／mass in 13 cases, 10 in immunocompetent patients and 3 in immunosuppressive patients respectively;(2)multiple nodules／masses in 15 cases, 10 in immunocompetent patients and 5 in immunosuppressive patients; (3) patchy or solid appearance in 6 cases, 4 in immunocompetent patients and 2 in immunosuppressive patients; (4) mixed type in 7cases,all in immunosuppressive patients; (5) mixed type accompanying with abnormal lymphadenectasis in mediastinum in 2 cases, both in immunocompetent children patients and the lymph nodes showed fusion, and necrosis. 85.3% (29/34) of nodule, mass and patchy solid types appeared unilaterally, 38.2% (13/34) in the upper lobe and 44.1% (15/34) in the lower lobe. Mixed type always be found bilaterally and both in upper and lower lobe the proportion was 77.8% (7/9). There was no significant difference in the lobe distribution of the 5 types. In immunocompetent group, it was mainly periphery distributed of 77.8% (21/27), however, in the immunosuppressive group, it always showed periphery and random distribution of 37.5% (6/16) and 50% (8/16) respectively. Ground glass opacity,hato sign,and air bronchogram were common to see, and the rates were 39.5% (17/43), 41.8% (18/43), 67.4% (29/43) respectively, and the cavity sign was rare (13.9%,6/43). These signs rates found in immunocompetent patients were 38.4% (10/27), 38.4% (10/27), 55.5% (15/27) and were 43.7% (7/16), 50% (8/16), 87.5% (14/16) in immunosuppressive group. Ground glass opacity and hato sign showed no significant difference in the two groups, while bronchogram sign likely occurred in the mmunosuppressive group.Conclusion The CT imaging is diverse in PPC. Lesions in immunocompetent patients show mainly nodule／lump types and peripheral areatus distribution, and show mixed type, prehperal and random distribution in immunosuppressive patients. Mixed type accompanying with abnormal enlargement, fusion, and necrosis of mediastinal lymph nodes in children should be highly concerned about PPC. Ground glass opacity,hato sign,and air bronchogram indicate this disease.