Objective：To explore the differences of clinical and CT features between lobar pneumonia and pneumonic lung cancer lo－calized to a single lobe. Methods：The clinical and CT data of 41 pneumonic lung cancer patients（lung cancer group） and 45 patients with lobar pneumonia（pneumonia group） were reviewed respectively. The age，sex，clinical symptoms，leukocyte count and CT find－ings of the two groups were compared. ROC curve was drawn for these parameters with statistical significance，and AUC was used to evaluate the diagnostic performance of each parameter. Results：For clinical features，the age of lung cancer group was older than that of pneumonia group（P<0.05）. No significant difference in gender was observed between both groups（P>0.05）. Cough，chest pain and hemoptysis were more common in lung cancer group（P<0.05），while fever and increased leukocyte count were more common in pneu－monia group（P<0.05）. No significant difference in the occurrence of expectoration was observed between both groups（P>0.05）. For CT features，no significant difference in the distribution of solitary consolidation was observed between both groups（P>0.05）. Air bronchogram sign with wither-stick shape，air-containing space，heterogeneous enhancement，and accompanying nodules were more common in lung cancer group（P<0.05）. No significant differences in the pleural effusion and ground-glass opacity around consolida－tion were observed between both groups. ROC curve analysis showed that air bronchogram sign with wither-stick shape was the most effective feature in the differential diagnosis of the two diseases，with an AUC of 0.807，and a sensitivity and specificity of 0.659 and 0.956，respectively. Conclusion：The clinical and CT features of lobar pneumonia and pneumonic lung cancer localized to a sin－gle lobe are different. Understanding these differences can help to improve the diagnostic accuracy of pneumonic lung cancer.