Objective To study the clinical and imaging features of pneumonia in lung cancer, and analyze the misdiagnosis reasons, put forward on the preventive strategy. Methods Retrospective analysis of 10 cases of pneumonia in patients with lung cancer, which was confirmed by pathology, clinical symptoms and signs, laboratory examination and CT imaging findings. Results 10 patients pathology were adenocarcinoma, 10 cases of CT manifestations in peripheral distribution, single lesions in 4 cases, 6 patients with multiple lesions. Air bronchogram see lesions in 9 cases, bronchial wall is irregular, stiff, and the distortion in 2 cases, distal occlusion in 3 cases, "bubble" in 7 cases, lesions around the texture distribution of nodules along the lung in 3 cases, enhanced scan lesions in see "blood vessels" in 6 cases, with pulmonary lymph node enlargement in 1 case. Clinical manifestations of 10 cases of cough, sputum, chest with 3 cases, 2 cases with chest pain, low thermal in 1 case, no obvious symptoms in 1 case. All of 10 patients have smoking history, smoking history 20-40 years, 10 to 60 cigarettes a day. Laboratory tests were no rise of tumor markers, moderately elevated white blood cell total 4 cases, 6 cases increased neutrophils. Conclusion Pneumonia, lung cancer has certain characteristics, clinical showing is often, when the preliminary clinical diagnosis is pneumonia and conventional anti-infective therapy effect is poor, the diagnosis of pneumonia should be questioned, type of lung cancer may be highly suspected pneumonia, should arrange active imaging review, get lung disease changes dynamic imaging, diagnostic difficulties, arrange fiber colonoscopy, pathology diagnosis, get early diagnosis and treatment.