Objective: To study on the characteristics of solitary pulmonary nodules with adenocarcinoma (ASPN) in 18F-fluorodeoxyglucose (18F-FDG) PET/CT for clinical reference.Methods: FDG PET/CT scans of 35 ASPNs were retrospectively analyzed on their features of image morphology and metabolism by a radiologist and 3 nuclear medicine physicians.The leisions were visualized and the regions of interest (ROI) were drawed, than the SUVmax are calculated by the PET/CT system.The △SUV is calculated by the formula: △SUV=(delay SUV-early SUV)/eary SUV×100%.The statistics analysis is used with SPSS11.5.Results: (1)Of 35 ASPNs, 15 (42.86%) ASPNs appear nodular FDG uptake, while 20 (57.14%)appear lamellar, cloudiness and unidentifiable FDG uptake.(2) There are 54.29% ASPNs (19/35)with SUVmax≥2.5, while 45.71% ASPNs (16/35)with SUVmax<2.5; (3)Of 35 ASPNs,24 (68.57%) are solitary nodules and 11 (31.43%) are ground glass nodules; (4) The SUVmax of ASPNs (4.22±3.52) on early FDG scan is significantly higher than that on delay scan (3.49±2.72) (t=-4.021, P<0.001) ; However, the SUVmax of ASPN on delay scan is higher or not than that on early scan, is dependent on the SUVmax on the early scan: 94.74%(18/19)ASPNs with SUVmax >2.5 have positive ASUVmax values, while there are only 56.25% (9/16) ASPNs with SUVmax <2.5 have positive △SUVmax values, P<0.01, and 66.67% (4/6) ASPNs with SUVmax≤1.0 have △SUVmaxs ≤ 0; (5) The average SUVmax (1.70±1.51) of ASPNs with well-differentiated adenocarcinoma is not only lower than that of ASPNs with poor-differentiated one (4.91±2.69), t=-3.951, P=0.001, its case ratio of△SUVmax>0 : ≤0 (10∶7 cases) is also significantly differently than that of ASPNs with poor-differentiated one (13∶1 cases), P=0.045; (6) There is a midrange positive correlation between the size of long and short axis and the SUVmax of ASPN, the P value is between 0.006 and0.030 and the R value is between 0.38 and 0.46.Conclusions: The imaging features of ASPNs FDG PET/CT on nodules metabolism and morphology has its specificity with large differences among different types of ASPNs.