The clinical data of 5 patients with pneumonia type lung cancer from January 2017 to January 2020 were retrospectively analyzed.The results showed that the clinical symptoms of the 5 patients were cough and expectoration.The infection index was mildly abnormal, and the tumor marker index was increased.After anti infection treatment, the effect was not good.The diagnosis of pneumonia type lung cancer was confirmed by improving the fiberoptic bronchoscopy biopsy.Due to the lack of specificity of clinical manifestations, if the early diagnosis of pneumonia type lung cancer can not be confirmed, the chest imaging can be reviewed after anti infection treatment, and the pathological basis can be obtained by timely improvement of fiberoptic bronchoscopy, bronchoalveolar lavage and lung biopsy.