Objective To analyze the CT findings of 40 patients with small cell lung cancer and their relationship with pathology(SCLC), and to improve the diagnostic accuracy of the disease. Methods Retrospective analysis was conducted on 40 pathologically confirmed patients in our hospital between April 2013 and April 2016. The CT findings were summarized. Results There were 35 cases with central type SCLC, and CT showed hilar lobulated masses or nodules. Enhanced scan mainly showed inhomogeneous enhancement. There were 14 cases with internal irregular necrosis, 16 cases with dilated blood vessels, and 7 cases with mild obstructive atelectasis or inflammation. There was mediastinal and pulmonary hilar lymph node metastasis in 21 cases and distant metastasis in 8 cases. Five cases had peripheral SCLC and the lesions were solitary nodules, without obvious burr on edges. Plain scan CT value was 18-36HU. Enhanced scan showed homogeneous enhancement in 2 cases of lesions and inhomogeneous enhancement in 3 cases. Conclusion Routine HE staining of patients with SCLC showed that cells are smaller and were extruded and distorted, nuclear to cytoplasmic ratio increases, and the positive rates of CD56 and Ki-67 reach 100%. Spiral CT findings include solid masses in the hilar region, with hilar and mediastinal lymph node metastasis, early hematogenous metastasis, and bronchial obstruction sign appearing later, which can be used to put forward diagnosis or suspected diagnosis. Confirmed diagnosis must rely on biopsy.